An attacker could cause a heap buffer overflow by getting a user to open an email that is greater than or equal to 2GB in size. This vulnerability was fixed in Thunderbird 157, Thunderbird 140.17, and Thunderbird 153.4.

The version of thunderbird installed on the remote host is prior to 153.5.1-1. It is, therefore, affected by multiple vulnerabilities as referenced in the ALAS2-2026-4057 advisory.

    Sandbox escape due to use-after-free in the DOM: Content Processes component. This vulnerability was fixed     in Firefox ESR 153.4, Firefox 157, Firefox ESR 115.42, and Firefox ESR 140.17. (CVE-2026-100762)

    Sandbox escape due to use-after-free in the DOM: Content Processes component. This vulnerability was fixed     in Firefox ESR 153.4, Firefox 157, Firefox ESR 115.42, and Firefox ESR 140.17. (CVE-2026-100770)

    Sandbox escape due to use-after-free in the DOM: Core & HTML component. This vulnerability was fixed in     Firefox ESR 153.4, Firefox 157, Firefox ESR 115.42, and Firefox ESR 140.17. (CVE-2026-100778)

    Sandbox escape due to use-after-free in the Graphics component. This vulnerability was fixed in Firefox     ESR 153.4, Firefox 157, Firefox ESR 115.42, and Firefox ESR 140.17. (CVE-2026-100786)

    Sandbox escape due to use-after-free in the DOM: Core & HTML component. This vulnerability was fixed in     Firefox ESR 153.4, Firefox 157, and Firefox ESR 140.17. (CVE-2026-100811)

    Sandbox escape due to use-after-free in the Widget: Gtk component. This vulnerability was fixed in Firefox     ESR 153.4, Firefox 157, and Firefox ESR 140.17. (CVE-2026-100818)

    Sandbox escape due to incorrect boundary conditions in the XPCOM component. This vulnerability was fixed     in Firefox ESR 153.4, Firefox 157, Firefox ESR 115.42, and Firefox ESR 140.17. (CVE-2026-100819)

    libexpat versions 2.7.2 through 2.8.5 contain an integer overflow vulnerability in expat_realloc()     function on 32-bit platforms when computing allocation sizes. Attackers supplying malicious XML to     applications parsing with vulnerable libexpat can cause heap buffer overflow, memory corruption, or denial     of service. (CVE-2026-102633)

    An attacker could cause a heap buffer overflow by getting a user to open an email that is greater than or     equal to 2GB in size. This vulnerability was fixed in Thunderbird 157, Thunderbird 140.17, and Thunderbird     153.4. (CVE-2026-103500)

    Privilege escalation in the Application Update component. This vulnerability was fixed in Firefox 158 and     Firefox ESR 153.5. (CVE-2026-109704)

    Use-after-free in the Storage: IndexedDB component. This vulnerability was fixed in Firefox 158, Firefox     ESR 115.43, and Firefox ESR 153.5. (CVE-2026-109706)

    Sandbox escape due to incorrect boundary conditions in the Networking component. This vulnerability was     fixed in Firefox 158 and Firefox ESR 153.5. (CVE-2026-109708)

    Information disclosure, privilege escalation in the Security: Process Sandboxing component. This     vulnerability was fixed in Firefox 158 and Firefox ESR 153.5. (CVE-2026-109709)

    Use-after-free in the Graphics: Text component. This vulnerability was fixed in Firefox 158, Firefox ESR     115.43, and Firefox ESR 153.5. (CVE-2026-109710)

    Use-after-free in the Graphics: Canvas2D component. This vulnerability was fixed in Firefox 158 and     Firefox ESR 153.5. (CVE-2026-109711)

    Sandbox escape due to uninitialized memory in the Graphics component. This vulnerability was fixed in     Firefox 158, Firefox ESR 115.43, and Firefox ESR 153.5. (CVE-2026-109712)

    Use-after-free in the Crash Reporting component. This vulnerability was fixed in Firefox 158 and Firefox     ESR 153.5. (CVE-2026-109713)

    Incorrect boundary conditions in the JavaScript Engine component. This vulnerability was fixed in Firefox     158, Firefox ESR 115.43, and Firefox ESR 153.5. (CVE-2026-109715)

    Incorrect boundary conditions in the JavaScript Engine component. This vulnerability was fixed in Firefox     158, Firefox ESR 115.43, and Firefox ESR 153.5. (CVE-2026-109716)

    Use-after-free in the DOM: Bindings (WebIDL) component. This vulnerability was fixed in Firefox 158 and     Firefox ESR 153.5. (CVE-2026-109717)

    Use-after-free in the XML component. This vulnerability was fixed in Firefox 158, Firefox ESR 115.43, and     Firefox ESR 153.5. (CVE-2026-109718)

    Race condition, use-after-free in the Graphics: CanvasWebGL component. This vulnerability was fixed in     Firefox 158, Firefox ESR 115.43, and Firefox ESR 153.5. (CVE-2026-109719)

    JIT miscompilation in the JavaScript: WebAssembly component. This vulnerability was fixed in Firefox 158     and Firefox ESR 153.5. (CVE-2026-109720)

    Incorrect boundary conditions in the JavaScript Engine: JIT component. This vulnerability was fixed in     Firefox 158 and Firefox ESR 153.5. (CVE-2026-109721)

    JIT miscompilation in the JavaScript Engine: JIT component. This vulnerability was fixed in Firefox 158,     Firefox ESR 115.43, and Firefox ESR 153.5. (CVE-2026-109722)

    Integer overflow in the Layout: Text and Fonts component. This vulnerability was fixed in Firefox 158 and     Firefox ESR 153.5. (CVE-2026-109723)

    Use-after-free in the DOM: Core & HTML component. This vulnerability was fixed in Firefox 158 and Firefox     ESR 153.5. (CVE-2026-109724)

    Use-after-free in the DOM: Core & HTML component. This vulnerability was fixed in Firefox 158, Firefox ESR     115.43, and Firefox ESR 153.5. (CVE-2026-109725)

    Use-after-free in the SVG component. This vulnerability was fixed in Firefox 158, Firefox ESR 115.43, and     Firefox ESR 153.5. (CVE-2026-109726)

    Use-after-free in the Audio/Video component. This vulnerability was fixed in Firefox 158, Firefox ESR     115.43, and Firefox ESR 153.5. (CVE-2026-109727)

    Use-after-free in the DOM: Animation component. This vulnerability was fixed in Firefox 158, Firefox ESR     115.43, and Firefox ESR 153.5. (CVE-2026-109728)

    Use-after-free in the JavaScript Engine: JIT component. This vulnerability was fixed in Firefox 158,     Firefox ESR 115.43, and Firefox ESR 153.5. (CVE-2026-109729)

    Integer overflow in the Graphics component. This vulnerability was fixed in Firefox 158, Firefox ESR     115.43, and Firefox ESR 153.5. (CVE-2026-109730)

    Incorrect boundary conditions in the Graphics: Canvas2D component. This vulnerability was fixed in Firefox     158 and Firefox ESR 153.5. (CVE-2026-109731)

    Use-after-free in the DOM: Streams component. This vulnerability was fixed in Firefox 158, Firefox ESR     115.43, and Firefox ESR 153.5. (CVE-2026-109732)

    JIT miscompilation in the JavaScript Engine: JIT component. This vulnerability was fixed in Firefox 158,     Firefox ESR 115.43, and Firefox ESR 153.5. (CVE-2026-109733)

    Mitigation bypass in the DOM: Security component. This vulnerability was fixed in Firefox 158 and Firefox     ESR 153.5. (CVE-2026-109734)

    Frame poisoning in the Layout component. This vulnerability was fixed in Firefox 158 and Firefox ESR     153.5. (CVE-2026-109736)

    Mitigation bypass in the Enterprise Policies component. This vulnerability was fixed in Firefox 158 and     Firefox ESR 153.5. (CVE-2026-109737)

    Use-after-free in the Audio/Video: Playback component. This vulnerability was fixed in Firefox 158 and     Firefox ESR 153.5. (CVE-2026-109738)

    Use-after-free in the Storage: Bucket File System component. This vulnerability was fixed in Firefox 158     and Firefox ESR 153.5. (CVE-2026-109741)

    Information disclosure in the PDF Viewer component. This vulnerability was fixed in Firefox 158 and     Firefox ESR 153.5. (CVE-2026-109742)

    Privilege escalation in the Panning and Zooming component. This vulnerability was fixed in Firefox 158 and     Firefox ESR 153.5. (CVE-2026-109743)

    Other issue in the DOM: File component. This vulnerability was fixed in Firefox 158 and Firefox ESR 153.5.
    (CVE-2026-109744)

    Sandbox escape due to uninitialized memory in the DOM: Web Serial component. This vulnerability was fixed     in Firefox 158 and Firefox ESR 153.5. (CVE-2026-109745)

    Information disclosure in the Networking component. This vulnerability was fixed in Firefox 158 and     Firefox ESR 153.5. (CVE-2026-109751)

    Use-after-free in the DOM: Workers component. This vulnerability was fixed in Firefox 158 and Firefox ESR     153.5. (CVE-2026-109752)

    Incorrect boundary conditions in the Layout component. This vulnerability was fixed in Firefox 158,     Firefox ESR 115.43, and Firefox ESR 153.5. (CVE-2026-109753)

    Incorrect boundary conditions in the DOM: Editor component. This vulnerability was fixed in Firefox 158     and Firefox ESR 153.5. (CVE-2026-109754)

    Privilege escalation in the DOM: Navigation component. This vulnerability was fixed in Firefox 158 and     Firefox ESR 153.5. (CVE-2026-109756)

    Sandbox escape due to race condition in the Networking component. This vulnerability was fixed in Firefox     158 and Firefox ESR 153.5. (CVE-2026-109757)

    Site isolation issue in the Networking component. This vulnerability was fixed in Firefox 158 and Firefox     ESR 153.5. (CVE-2026-109759)

    Mitigation bypass in the Networking: HTTP component. This vulnerability was fixed in Firefox 158 and     Firefox ESR 153.5. (CVE-2026-109760)

    Incorrect boundary conditions in the SVG component. This vulnerability was fixed in Firefox 158 and     Firefox ESR 153.5. (CVE-2026-109762)

    Mitigation bypass in the File Handling component. This vulnerability was fixed in Firefox 158 and Firefox     ESR 153.5. (CVE-2026-109763)

    Mitigation bypass in the Enterprise Policies component. This vulnerability was fixed in Firefox 158 and     Firefox ESR 153.5. (CVE-2026-109764)

    Race condition, use-after-free in the Graphics: Text component. This vulnerability was fixed in Firefox     158 and Firefox ESR 153.5. (CVE-2026-109765)

    Mitigation bypass in the Enterprise Policies component. This vulnerability was fixed in Firefox 158 and     Firefox ESR 153.5. (CVE-2026-109766)

    Information disclosure in the Networking component. This vulnerability was fixed in Firefox 158 and     Firefox ESR 153.5. (CVE-2026-109767)

    Spoofing issue in the DOM: Web Serial component. This vulnerability was fixed in Firefox 158 and Firefox     ESR 153.5. (CVE-2026-109770)

    Denial-of-service in the WebRTC component. This vulnerability was fixed in Firefox 158 and Firefox ESR     153.5. (CVE-2026-109775)

    Race condition in the XPCOM component. This vulnerability was fixed in Firefox 158 and Firefox ESR 153.5.
    (CVE-2026-109776)

    Information disclosure in the Storage: IndexedDB component. This vulnerability was fixed in Firefox 158     and Firefox ESR 153.5. (CVE-2026-109777)

    Privilege escalation in the WebExtensions component. This vulnerability was fixed in Firefox 158 and     Firefox ESR 153.5. (CVE-2026-109778)

    Denial-of-service in the Printing: Output component. This vulnerability was fixed in Firefox 158 and     Firefox ESR 153.5. (CVE-2026-109781)

    Mitigation bypass in the File Handling component. This vulnerability was fixed in Firefox ESR 153.5.
    (CVE-2026-109782)

    Mitigation bypass in the File Handling component. This vulnerability was fixed in Firefox ESR 153.5.
    (CVE-2026-109783)

    A malicious, compromised, or MITM-controlled Exchange server can return a single well-formed SOAP response     containing an element with enough attributes to keep Thunderbird's main thread CPU-bound for seconds to     hours. This vulnerability was fixed in Thunderbird 158 and Thunderbird 153.5. (CVE-2026-110249)

    When setting up an account, Thunderbird's Exchange AutoDiscover lookup also queried the domain's     AutoDiscover service over plain HTTP. Due to a bug, that unencrypted request included the credentials the     user had entered, allowing a network attacker to obtain the user's password. This vulnerability was fixed     in Thunderbird 158.0.1 and Thunderbird 153.5.1. (CVE-2026-113866)

    Thunderbird did not escape attribute values when serializing outgoing XMPP stanzas. Because values from     incoming requests were echoed back in automatic replies, a remote XMPP user could send a crafted request     that caused Thunderbird to inject arbitrary stanzas into the user's connection, which the server would     then process as if sent by the user. This could be used to send messages or change contact and     subscription settings on behalf of the user, without any interaction. This bug only affects Thunderbird's     chat feature with XMPP accounts. This vulnerability was fixed in Thunderbird 158.0.1 and Thunderbird     153.5.1. (CVE-2026-113867)

    When authenticating to a POP3 or SMTP server using NTLM, Thunderbird did not check whether the server's     challenge was valid base64. A malicious server could send a challenge that caused Thunderbird to include     uninitialized heap memory in its NTLM response, disclosing that memory to the server. A challenge     consisting only of base64 padding also caused an out-of-bounds read, crashing Thunderbird. This affected     accounts configured to use NTLM or GSSAPI authentication. The uninitialized memory disclosure only     affected NTLM. This vulnerability was fixed in Thunderbird 158.0.1 and Thunderbird 153.5.1.
    (CVE-2026-113868)

    Expat through 2.8.4 fails to validate low surrogates following high surrogates in UTF-16 input, allowing     malformed UTF-16 sequences to be accepted. Attackers can craft UTF-16 encoded XML with lone high     surrogates that consume following code units, hiding markup characters from the parser and enabling XML     injection attacks. (CVE-2026-93990)

Tenable has extracted the preceding description block directly from the tested product security advisory.

Note that Nessus has not tested for these issues but has instead relied only on the application's self-reported version number.

The AlmaLinux 9.2 host has a package installed that is affected by multiple vulnerabilities as referenced in the TuxCare ALMALINUX9.2:CLSA-2026:1792779937 advisory.

  - Incorrect boundary conditions in the Audio/Video: Playback component. This vulnerability was fixed in     Firefox ESR 153.4, Thunderbird 157, Thunderbird 140.17, Thunderbird 153.4, Firefox 157, Firefox ESR     115.42, and Firefox ESR 140.17. (CVE-2026-100756)

  - Use-after-free in the Widget component. This vulnerability was fixed in Firefox ESR 153.4, Thunderbird     157, Thunderbird 140.17, Thunderbird 153.4, Firefox 157, Firefox ESR 115.42, and Firefox ESR 140.17.
    (CVE-2026-100757)

  - Sandbox escape in the DOM: Navigation component. This vulnerability was fixed in Firefox ESR 153.4,     Thunderbird 157, Thunderbird 140.17, Thunderbird 153.4, Firefox 157, Firefox ESR 115.42, and Firefox ESR     140.17. (CVE-2026-100758)

  - Uninitialized memory in the Storage: Quota Manager component. This vulnerability was fixed in Firefox ESR     153.4, Thunderbird 157, Thunderbird 140.17, Thunderbird 153.4, Firefox 157, Firefox ESR 115.42, and     Firefox ESR 140.17. (CVE-2026-100759)

  - Sandbox escape in the Security: Process Sandboxing component. This vulnerability was fixed in Firefox ESR     153.4, Thunderbird 157, Thunderbird 153.4, and Firefox 157. (CVE-2026-100760)

Note that Nessus has not tested for these issues but has instead relied only on the application's self-reported version number.

The remote SUSE Linux SLED15 / SLED_SAP15 / SLES15 / SLES_SAP15 host has packages installed that are affected by multiple vulnerabilities as referenced in the SUSE-SU-2026:4627-1 advisory.

    Update to Mozilla Thunderbird 153.4 (MFSA 2026-96, MFSA 2026-103, bsc#1280371, bsc#1282929):

    - CVE-2026-92005: Use-after-free in the Audio/Video: Web Codecs component.
    - CVE-2026-92006: Privilege escalation due to incorrect boundary conditions in the Graphics: CanvasWebGL     component.
    - CVE-2026-92007: Privilege escalation due to incorrect boundary conditions in the Graphics: CanvasWebGL     component.
    - CVE-2026-92008: Privilege escalation due to incorrect boundary conditions in the Graphics: CanvasWebGL     component.
    - CVE-2026-92009: Privilege escalation due to incorrect boundary conditions in the Graphics: CanvasWebGL     component.
    - CVE-2026-92010: Privilege escalation due to incorrect boundary conditions in the Graphics: CanvasWebGL     component.
    - CVE-2026-92011: Privilege escalation due to incorrect boundary conditions in the Graphics: CanvasWebGL     component.
    - CVE-2026-92012: Privilege escalation due to incorrect boundary conditions in the Graphics: CanvasWebGL     component.
    - CVE-2026-92013: Privilege escalation due to incorrect boundary conditions in the Graphics: CanvasWebGL     component.
    - CVE-2026-92015: Privilege escalation in the WebExtensions component.
    - CVE-2026-92016: Use-after-free in the Disability Access APIs component.
    - CVE-2026-92017: Privilege escalation in the DOM: Service Workers component.
    - CVE-2026-92018: Sandbox escape in the DOM: Core & HTML component.
    - CVE-2026-92019: Mitigation bypass in the Remote Settings Client component.
    - CVE-2026-92020: Privilege escalation due to incorrect boundary conditions in the Graphics: WebRender     component.
    - CVE-2026-92022: Use-after-free in the DOM: HTML Parser component.
    - CVE-2026-92023: Use-after-free in the XML component.
    - CVE-2026-92024: Use-after-free in the SVG component.
    - CVE-2026-92025: Use-after-free in the DOM: Navigation component.
    - CVE-2026-92026: Use-after-free in the Networking component.
    - CVE-2026-92027: Use-after-free in the DOM: Streams component.
    - CVE-2026-92028: Use-after-free in the DOM: Core & HTML component.
    - CVE-2026-92029: Use-after-free in the SVG component.
    - CVE-2026-92030: Mitigation bypass in the DOM: Copy & Paste and Drag & Drop component.
    - CVE-2026-92031: Information disclosure in the Graphics: ImageLib component.
    - CVE-2026-92032: Sandbox escape due to invalid pointer in the Graphics component.
    - CVE-2026-92035: Sandbox escape due to incorrect boundary conditions in the Graphics component.
    - CVE-2026-92038: Mitigation bypass in the Remote Settings Client component.
    - CVE-2026-92039: Mitigation bypass in the DOM: Notifications component.
    - CVE-2026-92041: Mitigation bypass in the DOM: Networking component.
    - CVE-2026-92042: Race condition in the DOM: Content Processes component.
    - CVE-2026-92043: Privilege escalation due to incorrect boundary conditions in the Audio/Video component.
    - CVE-2026-92044: Information disclosure in the Networking: HTTP component.
    - CVE-2026-92045: Sandbox escape due to incorrect boundary conditions in the WebRTC component.
    - CVE-2026-92046: Use-after-free in the Graphics component.
    - CVE-2026-92047: Privilege escalation in the Crash Reporting component.
    - CVE-2026-92048: Sandbox escape due to incorrect boundary conditions in the Widget: Win32 component.
    - CVE-2026-92049: Use-after-free in the Widget: Win32 component.
    - CVE-2026-92052: Privilege escalation due to uninitialized memory in the Graphics: CanvasWebGL component.
    - CVE-2026-92053: Privilege escalation in the Graphics: CanvasWebGL component.
    - CVE-2026-92054: Privilege escalation in the Memory component.
    - CVE-2026-92055: Privilege escalation in the DevTools component.
    - CVE-2026-92056: Use-after-free in the Graphics: Text component.
    - CVE-2026-92057: Mitigation bypass in the Enterprise Policies component.
    - CVE-2026-92058: Use-after-free in the Graphics component.
    - CVE-2026-92059: Incorrect boundary conditions in the DOM: Editor component.
    - CVE-2026-92060: Use-after-free in the Internationalization component.
    - CVE-2026-92062: Privilege escalation in the Session Restore component.
    - CVE-2026-92064: Sandbox escape due to incorrect boundary conditions in the Widget: Win32 component.
    - CVE-2026-92065: Sandbox escape due to incorrect boundary conditions in the Widget: Win32 component.
    - CVE-2026-92067: Use-after-free in the Widget: Gtk component.
    - CVE-2026-92068: Site isolation issue in the Reader Mode component.
    - CVE-2026-92069: Spoofing issue in the DOM: Navigation component.
    - CVE-2026-92070: Information disclosure in the Networking component.
    - CVE-2026-92071: Sandbox escape due to incorrect boundary conditions in the Widget: Win32 component.
    - CVE-2026-92072: Incorrect boundary conditions in the Safe Browsing component.
    - CVE-2026-92073: Privilege escalation in the Enterprise Policies component.
    - CVE-2026-92074: Mitigation bypass in the Popup Blocker component.
    - CVE-2026-92075: Mitigation bypass in the Networking component.
    - CVE-2026-92076: Incorrect boundary conditions in the Networking component.
    - CVE-2026-92077: Denial-of-service in the SVG component.
    - CVE-2026-92078: Denial-of-service in the Security component.
    - CVE-2026-92079: Mitigation bypass in the Widget: Win32 component.
    - CVE-2026-92238: Ambiguous parsing of mail headers.
    - CVE-2026-92239: Buffer overrun in IMAP.
    - CVE-2026-92240: Out-of-bounds read in IMAP response parser.
    - CVE-2026-96869: Information disclosure in the Networking component.
    - CVE-2026-100756: Incorrect boundary conditions in the Audio/Video: Playback component.
    - CVE-2026-100757: Use-after-free in the Widget component.
    - CVE-2026-100758: Sandbox escape in the DOM: Navigation component.
    - CVE-2026-100759: Uninitialized memory in the Storage: Quota Manager component.
    - CVE-2026-100760: Sandbox escape in the Security: Process Sandboxing component.
    - CVE-2026-100762: Sandbox escape due to use-after-free in the DOM: Content Processes component.
    - CVE-2026-100765: Use-after-free in the JavaScript: WebAssembly component.
    - CVE-2026-100766: Information disclosure in the Networking: JAR component.
    - CVE-2026-100767: Use-after-free in the Networking: Cache component.
    - CVE-2026-100769: Use-after-free in the JavaScript: WebAssembly component.
    - CVE-2026-100770: Sandbox escape due to use-after-free in the DOM: Content Processes component.
    - CVE-2026-100771: Undefined behavior in the DOM: Streams component.
    - CVE-2026-100772: Use-after-free in the DOM: Core & HTML component.
    - CVE-2026-100773: Use-after-free in the Storage: IndexedDB component.
    - CVE-2026-100774: Use-after-free in the DOM: Core & HTML component.
    - CVE-2026-100775: Sandbox escape in the Graphics component.
    - CVE-2026-100776: Use-after-free in the JavaScript: WebAssembly component.
    - CVE-2026-100777: Use-after-free in the Graphics: Canvas2D component.
    - CVE-2026-100778: Sandbox escape due to use-after-free in the DOM: Core & HTML component.
    - CVE-2026-100779: Use-after-free in the XSLT component.
    - CVE-2026-100780: Use-after-free in the DOM: Core & HTML component.
    - CVE-2026-100781: Sandbox escape due to incorrect boundary conditions in the Graphics: WebRender     component.
    - CVE-2026-100782: Privilege escalation due to incorrect boundary conditions in the Graphics component.
    - CVE-2026-100783: Uninitialized memory in the Audio/Video component.
    - CVE-2026-100784: Use-after-free in the Layout: Text and Fonts component.
    - CVE-2026-100785: Use-after-free in the DOM: Core & HTML component.
    - CVE-2026-100786: Sandbox escape due to use-after-free in the Graphics component.
    - CVE-2026-100787: Sandbox escape in the XUL component.
    - CVE-2026-100788: Invalid pointer in the JavaScript: WebAssembly component.
    - CVE-2026-100789: Use-after-free in the Graphics: Canvas2D component.
    - CVE-2026-100790: Use-after-free in the XSLT component.
    - CVE-2026-100791: Use-after-free in the DOM: Core & HTML component.
    - CVE-2026-100792: JIT miscompilation in the JavaScript: WebAssembly component.
    - CVE-2026-100794: Sandbox escape due to incorrect boundary conditions in the Internationalization     component.
    - CVE-2026-100797: Privilege escalation due to use-after-free in the Graphics: WebRender component.
    - CVE-2026-100798: Cryptography misuse in Storage: Quota Manager component.
    - CVE-2026-100800: Sandbox escape due to use-after-free in the Disability Access APIs component.
    - CVE-2026-100801: Privilege escalation in the DLL Services component.
    - CVE-2026-100803: Same-origin policy bypass in the WebExtensions component.
    - CVE-2026-100806: Uninitialized memory in the Graphics: WebGPU component.
    - CVE-2026-100807: Privilege escalation in the DOM: Service Workers component.
    - CVE-2026-100808: Mitigation bypass in the DOM: Service Workers component.
    - CVE-2026-100809: Same-origin policy bypass in the DevTools component.
    - CVE-2026-100811: Sandbox escape due to use-after-free in the DOM: Core & HTML component.
    - CVE-2026-100812: Denial-of-service in the Graphics component.
    - CVE-2026-100814: Incorrect boundary conditions in the JavaScript Engine: JIT component.
    - CVE-2026-100815: Use-after-free in the CSS Parsing and Computation component.
    - CVE-2026-100816: Site isolation issue in the DOM: Networking component.
    - CVE-2026-100818: Sandbox escape due to use-after-free in the Widget: Gtk component.
    - CVE-2026-100819: Sandbox escape due to incorrect boundary conditions in the XPCOM component.
    - CVE-2026-100820: Privilege escalation in the Address Bar component.
    - CVE-2026-100821: Site isolation issue in the Panning and Zooming component.
    - CVE-2026-100822: Spoofing issue in the Networking: HTTP component.
    - CVE-2026-100824: Privilege escalation in the Places component.
    - CVE-2026-100825: Use-after-free in the JavaScript Engine: JIT component.
    - CVE-2026-100826: Denial-of-service in the Storage: StorageManager component.
    - CVE-2026-100828: Mitigation bypass in the Bookmarks & History component.
    - CVE-2026-100829: Mitigation bypass in the DOM: Security component.
    - CVE-2026-100830: Mitigation bypass in the DOM: Navigation component.
    - CVE-2026-100831: Use-after-free in the DOM: UI Events & Focus Handling component.
    - CVE-2026-100832: Use-after-free in the Graphics: Canvas2D component.
    - CVE-2026-103500: Heap buffer overflow opening large email.

    Changes for MozillaThunderbird:

     * changed: RNP command-line utilities are no longer included      with Thunderbird (bmo#2068130)
     * changed: Thundermail built-in add-on updated to v2.0.16      (bmo#2071989)
     * fixed: Ctrl+Shift+K could fail to open the Quick Filter UI      (bmo#2062942)
     * fixed: Nested S/MIME signed parts could fail to render      (bmo#2062971)
     * fixed: Thunderbird could hang when waiting for IMAP server      greeting during account setup (bmo#2028760)
     * fixed: Gmail OAuth2 authentication could intermittently fail      on Windows (bmo#2063816)
     * fixed: `AppUpdatePin` policy did not prevent Thunderbird from      updating beyond pinned version (bmo#1910603)
     * fixed: 'What's New?' linked to Release channel notes instead      of ESR release notes (bmo#2073813)
     * fixed: Detached attachment links were truncated when folder      path contained `&` (bmo#2060451)
     * fixed: Save All, Detach All, and Delete All failed after      deleting one attachment (bmo#2057025)
     * fixed: Blank 1970-dated messages could appear from incomplete      message file copies (bmo#209501)
     * fixed: Forwarded messages could display incorrect encoding      (bmo#2059963)
     * fixed: Manual Get Messages failed after startup until      toggling offline mode (bmo#2057431)
     * fixed: Thunderbird could crash on shutdown while waiting for      OAuth2 password entry (bmo#1524247)

Tenable has extracted the preceding description block directly from the SUSE security advisory.

Note that Nessus has not tested for these issues but has instead relied only on the application's self-reported version number.

The remote Debian 12 host has packages installed that are affected by multiple vulnerabilities as referenced in the dla-4810 advisory.

    - -------------------------------------------------------------------------     Debian LTS Advisory DLA-4810-1                debian-lts@lists.debian.org     https://www.debian.org/lts/security/               Emilio Pozuelo Monfort     October 02, 2026                              https://wiki.debian.org/LTS
    - -------------------------------------------------------------------------

    Package        : thunderbird     Version        : 1:140.17.0esr-1~deb12u1     CVE ID         : CVE-2026-92035 CVE-2026-96869 CVE-2026-100756 CVE-2026-100757                      CVE-2026-100758 CVE-2026-100759 CVE-2026-100762 CVE-2026-100766                      CVE-2026-100767 CVE-2026-100769 CVE-2026-100770 CVE-2026-100771                      CVE-2026-100772 CVE-2026-100773 CVE-2026-100774 CVE-2026-100775                      CVE-2026-100776 CVE-2026-100777 CVE-2026-100778 CVE-2026-100779                      CVE-2026-100780 CVE-2026-100781 CVE-2026-100782 CVE-2026-100783                      CVE-2026-100784 CVE-2026-100785 CVE-2026-100786 CVE-2026-100788                      CVE-2026-100789 CVE-2026-100790 CVE-2026-100791 CVE-2026-100792                      CVE-2026-100794 CVE-2026-100797 CVE-2026-100801 CVE-2026-100803                      CVE-2026-100807 CVE-2026-100811 CVE-2026-100818 CVE-2026-100819                      CVE-2026-100820 CVE-2026-100821 CVE-2026-100832 CVE-2026-103500

    Multiple security issues were discovered in Thunderbird, which could     result in the execution of arbitrary code.

    For Debian 12 bookworm, these problems have been fixed in version     1:140.17.0esr-1~deb12u1.

    We recommend that you upgrade your thunderbird packages.

    For the detailed security status of thunderbird please refer to     its security tracker page at:
    https://security-tracker.debian.org/tracker/thunderbird

    Further information about Debian LTS security advisories, how to apply     these updates to your system and frequently asked questions can be     found at: https://wiki.debian.org/LTS

Tenable has extracted the preceding description block directly from the Debian security advisory.

Note that Nessus has not tested for these issues but has instead relied only on the application's self-reported version number.

The remote Debian 13 host has packages installed that are affected by multiple vulnerabilities as referenced in the dsa-6536 advisory.

    - -------------------------------------------------------------------------     Debian Security Advisory DSA-6536-1                   security@debian.org     https://www.debian.org/security/                       Moritz Muehlenhoff     October 01, 2026                      https://www.debian.org/security/faq
    - -------------------------------------------------------------------------

    Package        : thunderbird     CVE ID         : CVE-2026-92035 CVE-2026-96869 CVE-2026-100756 CVE-2026-100757                      CVE-2026-100758 CVE-2026-100759 CVE-2026-100762 CVE-2026-100766                      CVE-2026-100767 CVE-2026-100769 CVE-2026-100770 CVE-2026-100771                      CVE-2026-100772 CVE-2026-100773 CVE-2026-100774 CVE-2026-100775                      CVE-2026-100776 CVE-2026-100777 CVE-2026-100778 CVE-2026-100779                      CVE-2026-100780 CVE-2026-100781 CVE-2026-100782 CVE-2026-100783                      CVE-2026-100784 CVE-2026-100785 CVE-2026-100786 CVE-2026-100788                      CVE-2026-100789 CVE-2026-100790 CVE-2026-100791 CVE-2026-100792                      CVE-2026-100794 CVE-2026-100797 CVE-2026-100801 CVE-2026-100803                      CVE-2026-100807 CVE-2026-100811 CVE-2026-100818 CVE-2026-100819                      CVE-2026-100820 CVE-2026-100821 CVE-2026-100832 CVE-2026-103500

    Multiple security issues were discovered in Thunderbird, which could     result in the execution of arbitrary code.

    For the stable distribution (trixie), these problems have been fixed in     version 1:140.17.0esr-1~deb13u1.

    We recommend that you upgrade your thunderbird packages.

    For the detailed security status of thunderbird please refer to     its security tracker page at:
    https://security-tracker.debian.org/tracker/thunderbird

    Further information about Debian Security Advisories, how to apply     these updates to your system and frequently asked questions can be     found at: https://www.debian.org/security/

    Mailing list: debian-security-announce@lists.debian.org

Tenable has extracted the preceding description block directly from the Debian security advisory.

Note that Nessus has not tested for these issues but has instead relied only on the application's self-reported version number.

The version of mozilla-thunderbird installed on the remote host is prior to 140.17.0esr / 153.4.0esr. It is, therefore, affected by multiple vulnerabilities as referenced in the SSA:2026-273-02 advisory.

    New mozilla-thunderbird packages are available for Slackware 15.0 and -current to fix security issues.

Tenable has extracted the preceding description block directly from the mozilla-thunderbird security advisory.

Note that Nessus has not tested for these issues but has instead relied only on the application's self-reported version number.

The Linux/Unix host has one or more packages installed that are impacted by a vulnerability without a vendor supplied patch available.

  - An attacker could cause a heap buffer overflow by getting a user to open an email that is greater than or     equal to 2GB in size. This vulnerability was fixed in Thunderbird 157, Thunderbird 140.17, and Thunderbird     153.4. (CVE-2026-103500)

Note that Nessus relies on the presence of the package as reported by the vendor.

The version of Thunderbird installed on the remote macOS or Mac OS X host is prior to 157.0. It is, therefore, affected by multiple vulnerabilities as referenced in the mfsa2026-101 advisory.

  - Use-after-free in the DOM: UI Events & Focus Handling component. This vulnerability was fixed in Firefox     ESR 153.4 and Firefox 157. (CVE-2026-100831)

  - Sandbox escape due to incorrect boundary conditions in the XPCOM component. This vulnerability was fixed     in Firefox ESR 153.4, Firefox 157, Firefox ESR 115.42, and Firefox ESR 140.17. (CVE-2026-100819)

  - An attacker could cause a heap buffer overflow by getting a user to open an email that is greater than or     equal to 2GB in size. (CVE-2026-103500)

  - Incorrect boundary conditions in the Audio/Video: Playback component. This vulnerability was fixed in     Firefox ESR 153.4, Firefox 157, Firefox ESR 115.42, and Firefox ESR 140.17. (CVE-2026-100756)

  - Use-after-free in the Widget component. This vulnerability was fixed in Firefox ESR 153.4, Firefox 157,     Firefox ESR 115.42, and Firefox ESR 140.17. (CVE-2026-100757)

Note that Nessus has not tested for these issues but has instead relied only on the application's self-reported version number.

The version of Thunderbird installed on the remote Windows host is prior to 157.0. It is, therefore, affected by multiple vulnerabilities as referenced in the mfsa2026-101 advisory.

  - Use-after-free in the DOM: UI Events & Focus Handling component. This vulnerability was fixed in Firefox     ESR 153.4 and Firefox 157. (CVE-2026-100831)

  - Sandbox escape due to incorrect boundary conditions in the XPCOM component. This vulnerability was fixed     in Firefox ESR 153.4, Firefox 157, Firefox ESR 115.42, and Firefox ESR 140.17. (CVE-2026-100819)

  - An attacker could cause a heap buffer overflow by getting a user to open an email that is greater than or     equal to 2GB in size. (CVE-2026-103500)

  - Incorrect boundary conditions in the Audio/Video: Playback component. This vulnerability was fixed in     Firefox ESR 153.4, Firefox 157, Firefox ESR 115.42, and Firefox ESR 140.17. (CVE-2026-100756)

  - Use-after-free in the Widget component. This vulnerability was fixed in Firefox ESR 153.4, Firefox 157,     Firefox ESR 115.42, and Firefox ESR 140.17. (CVE-2026-100757)

Note that Nessus has not tested for these issues but has instead relied only on the application's self-reported version number.

The version of Thunderbird installed on the remote macOS or Mac OS X host is prior to 153.4. It is, therefore, affected by multiple vulnerabilities as referenced in the mfsa2026-103 advisory.

  - Sandbox escape due to incorrect boundary conditions in the XPCOM component. This vulnerability was fixed     in Firefox ESR 153.4, Firefox 157, Firefox ESR 115.42, and Firefox ESR 140.17. (CVE-2026-100819)

  - Use-after-free in the Graphics: Canvas2D component. This vulnerability was fixed in Firefox ESR 153.4,     Firefox ESR 115.42, and Firefox ESR 140.17. (CVE-2026-100832)

  - An attacker could cause a heap buffer overflow by getting a user to open an email that is greater than or     equal to 2GB in size. (CVE-2026-103500)

  - Incorrect boundary conditions in the Audio/Video: Playback component. This vulnerability was fixed in     Firefox ESR 153.4, Firefox 157, Firefox ESR 115.42, and Firefox ESR 140.17. (CVE-2026-100756)

  - Use-after-free in the Widget component. This vulnerability was fixed in Firefox ESR 153.4, Firefox 157,     Firefox ESR 115.42, and Firefox ESR 140.17. (CVE-2026-100757)

Note that Nessus has not tested for these issues but has instead relied only on the application's self-reported version number.

The version of Thunderbird installed on the remote Windows host is prior to 153.4. It is, therefore, affected by multiple vulnerabilities as referenced in the mfsa2026-103 advisory.

  - Sandbox escape due to incorrect boundary conditions in the XPCOM component. This vulnerability was fixed     in Firefox ESR 153.4, Firefox 157, Firefox ESR 115.42, and Firefox ESR 140.17. (CVE-2026-100819)

  - Use-after-free in the Graphics: Canvas2D component. This vulnerability was fixed in Firefox ESR 153.4,     Firefox ESR 115.42, and Firefox ESR 140.17. (CVE-2026-100832)

  - An attacker could cause a heap buffer overflow by getting a user to open an email that is greater than or     equal to 2GB in size. (CVE-2026-103500)

  - Incorrect boundary conditions in the Audio/Video: Playback component. This vulnerability was fixed in     Firefox ESR 153.4, Firefox 157, Firefox ESR 115.42, and Firefox ESR 140.17. (CVE-2026-100756)

  - Use-after-free in the Widget component. This vulnerability was fixed in Firefox ESR 153.4, Firefox 157,     Firefox ESR 115.42, and Firefox ESR 140.17. (CVE-2026-100757)

Note that Nessus has not tested for these issues but has instead relied only on the application's self-reported version number.

The version of Thunderbird installed on the remote macOS or Mac OS X host is prior to 140.17. It is, therefore, affected by multiple vulnerabilities as referenced in the mfsa2026-102 advisory.

  - Sandbox escape due to incorrect boundary conditions in the Graphics component. This vulnerability was     fixed in Firefox 156, Firefox ESR 153.3, Thunderbird 156, Thunderbird 153.3, Firefox ESR 115.42, and     Firefox ESR 140.17. (CVE-2026-92035)

  - An attacker could cause a heap buffer overflow by getting a user to open an email that is greater than or     equal to 2GB in size. (CVE-2026-103500)

  - Incorrect boundary conditions in the Audio/Video: Playback component. This vulnerability was fixed in     Firefox ESR 153.4, Firefox 157, Firefox ESR 115.42, and Firefox ESR 140.17. (CVE-2026-100756)

  - Use-after-free in the Widget component. This vulnerability was fixed in Firefox ESR 153.4, Firefox 157,     Firefox ESR 115.42, and Firefox ESR 140.17. (CVE-2026-100757)

  - Sandbox escape in the DOM: Navigation component. This vulnerability was fixed in Firefox ESR 153.4,     Firefox 157, Firefox ESR 115.42, and Firefox ESR 140.17. (CVE-2026-100758)

Note that Nessus has not tested for these issues but has instead relied only on the application's self-reported version number.

The version of Thunderbird installed on the remote Windows host is prior to 140.17. It is, therefore, affected by multiple vulnerabilities as referenced in the mfsa2026-102 advisory.

  - Sandbox escape due to incorrect boundary conditions in the Graphics component. This vulnerability was     fixed in Firefox 156, Firefox ESR 153.3, Thunderbird 156, Thunderbird 153.3, Firefox ESR 115.42, and     Firefox ESR 140.17. (CVE-2026-92035)

  - An attacker could cause a heap buffer overflow by getting a user to open an email that is greater than or     equal to 2GB in size. (CVE-2026-103500)

  - Incorrect boundary conditions in the Audio/Video: Playback component. This vulnerability was fixed in     Firefox ESR 153.4, Firefox 157, Firefox ESR 115.42, and Firefox ESR 140.17. (CVE-2026-100756)

  - Use-after-free in the Widget component. This vulnerability was fixed in Firefox ESR 153.4, Firefox 157,     Firefox ESR 115.42, and Firefox ESR 140.17. (CVE-2026-100757)

  - Sandbox escape in the DOM: Navigation component. This vulnerability was fixed in Firefox ESR 153.4,     Firefox 157, Firefox ESR 115.42, and Firefox ESR 140.17. (CVE-2026-100758)

Note that Nessus has not tested for these issues but has instead relied only on the application's self-reported version number.

ID	Name	Product	Family	Type	Severity
374387	Amazon Linux 2 : thunderbird (ALAS-2026-4057)	Nessus	Amazon Linux Local Security Checks	Local	high
371611	AlmaLinux 9.2 [TuxCare] Security Update: thunderbird Multiple Vulnerabilities (ALMALINUX9.2:CLSA-2026:1792779937)	Nessus	Alma Linux Local Security Checks	Local	medium
365333	SUSE SLED15: MozillaThunderbird / MozillaThunderbird-translations-common / etc (SUSE-SU-2026:4627-1)	Nessus	SuSE Local Security Checks	Local	medium
362458	Debian dla-4810 : thunderbird - security update	Nessus	Debian Local Security Checks	Local	medium
362453	Debian dsa-6536 : thunderbird - security update	Nessus	Debian Local Security Checks	Local	medium
358451	Slackware Linux 15.0 / current mozilla-thunderbird Multiple Vulnerabilities (SSA:2026-273-02)	Nessus	Slackware Local Security Checks	Local	medium
358366	Linux Distros Unpatched Vulnerability : CVE-2026-103500	Nessus	Misc.	Local	medium
353287	Mozilla Thunderbird < 157.0	Nessus	MacOS X Local Security Checks	Local	medium
353286	Mozilla Thunderbird < 157.0	Nessus	Windows	Local	medium
353285	Mozilla Thunderbird < 153.4	Nessus	MacOS X Local Security Checks	Local	medium
353284	Mozilla Thunderbird < 153.4	Nessus	Windows	Local	medium
353283	Mozilla Thunderbird < 140.17	Nessus	MacOS X Local Security Checks	Local	medium
353282	Mozilla Thunderbird < 140.17	Nessus	Windows	Local	medium

Detections

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CVE-2026-103500

medium

Tenable Plugins

high

medium

medium

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medium

medium

medium

medium

medium

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medium