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.

The AlmaLinux 9.2 host has a package installed that is affected by multiple vulnerabilities as referenced in the TuxCare ALMALINUX9.2:CLSA-2026:1793952112 advisory.

  - Sandbox escape due to incorrect boundary conditions in the Graphics: CanvasWebGL component. This     vulnerability was fixed in Firefox 159, Firefox ESR 153.6, Thunderbird 159, and Thunderbird 153.6.
    (CVE-2026-117988)

  - Use-after-free in the Layout: Text and Fonts component. This vulnerability was fixed in Firefox 159,     Firefox ESR 153.6, Thunderbird 159, and Thunderbird 153.6. (CVE-2026-117877, CVE-2026-117902)

  - Use-after-free in the DOM: Core & HTML component. This vulnerability was fixed in Firefox 159, Firefox ESR     115.44, Firefox ESR 153.6, Thunderbird 159, and Thunderbird 153.6. (CVE-2026-117881, CVE-2026-117887,     CVE-2026-117919, CVE-2026-117925, CVE-2026-117936, CVE-2026-117949, CVE-2026-117951)

  - Same-origin policy bypass in the Address Bar component. This vulnerability was fixed in Firefox 159,     Firefox ESR 153.6, Thunderbird 159, and Thunderbird 153.6. (CVE-2026-117965)

  - Use-after-free in the Layout component. This vulnerability was fixed in Firefox 159, Firefox ESR 115.44,     Firefox ESR 153.6, Thunderbird 159, and Thunderbird 153.6. (CVE-2026-117882)

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 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 remote Debian 12 host has packages installed that are affected by multiple vulnerabilities as referenced in the dla-4863 advisory.

    - -------------------------------------------------------------------------     Debian LTS Advisory DLA-4863-1                debian-lts@lists.debian.org     https://www.debian.org/lts/security/               Emilio Pozuelo Monfort     October 26, 2026                              https://wiki.debian.org/LTS
    - -------------------------------------------------------------------------

    Package        : thunderbird     Version        : 1:153.5.1esr-1~deb12u1     CVE ID         : CVE-2026-109705 CVE-2026-109706 CVE-2026-109707 CVE-2026-109708                      CVE-2026-109709 CVE-2026-109710 CVE-2026-109711 CVE-2026-109712                      CVE-2026-109713 CVE-2026-109715 CVE-2026-109716 CVE-2026-109717                      CVE-2026-109718 CVE-2026-109719 CVE-2026-109720 CVE-2026-109721                      CVE-2026-109722 CVE-2026-109723 CVE-2026-109724 CVE-2026-109725                      CVE-2026-109726 CVE-2026-109727 CVE-2026-109728 CVE-2026-109729                      CVE-2026-109730 CVE-2026-109731 CVE-2026-109732 CVE-2026-109733                      CVE-2026-109734 CVE-2026-109736 CVE-2026-109737 CVE-2026-109738                      CVE-2026-109741 CVE-2026-109742 CVE-2026-109743 CVE-2026-109744                      CVE-2026-109745 CVE-2026-109751 CVE-2026-109752 CVE-2026-109753                      CVE-2026-109754 CVE-2026-109756 CVE-2026-109757 CVE-2026-109759                      CVE-2026-109760 CVE-2026-109762 CVE-2026-109763 CVE-2026-109764                      CVE-2026-109765 CVE-2026-109766 CVE-2026-109767 CVE-2026-109770                      CVE-2026-109775 CVE-2026-109776 CVE-2026-109777 CVE-2026-109778                      CVE-2026-109781 CVE-2026-110249 CVE-2026-113470 CVE-2026-113866                      CVE-2026-113867 CVE-2026-113868

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

    Debian follows the Thunderbird upstream releases. Support for the 140.x     series has ended, so starting with this update we're now following the     153.x series.

    For Debian 12 bookworm, these problems have been fixed in version     1:153.5.1esr-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 version of Thunderbird installed on the remote Windows host is prior to 153.5.1. It is, therefore, affected by multiple vulnerabilities as referenced in the mfsa2026-115 advisory.

  - Mozilla blocked compromised intermediate eMudhra certificates via OneCRL on the 17th of October which was     distributed to clients via RemoteSettings the same day. This update contains the updated OneCRL block     list, ensuring clients will block the compromised certificates even if RemoteSettings is disabled by     policy or otherwise unavailable in the user's network environment. (CVE-2026-113470)

  - 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. (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. (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. (CVE-2026-113868)

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 153.5.1. It is, therefore, affected by multiple vulnerabilities as referenced in the mfsa2026-115 advisory.

  - Mozilla blocked compromised intermediate eMudhra certificates via OneCRL on the 17th of October which was     distributed to clients via RemoteSettings the same day. This update contains the updated OneCRL block     list, ensuring clients will block the compromised certificates even if RemoteSettings is disabled by     policy or otherwise unavailable in the user's network environment. (CVE-2026-113470)

  - 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. (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. (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. (CVE-2026-113868)

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 158.0.1. It is, therefore, affected by multiple vulnerabilities as referenced in the mfsa2026-114 advisory.

  - Mozilla blocked compromised intermediate eMudhra certificates via OneCRL on the 17th of October which was     distributed to clients via RemoteSettings the same day. This update contains the updated OneCRL block     list, ensuring clients will block the compromised certificates even if RemoteSettings is disabled by     policy or otherwise unavailable in the user's network environment. (CVE-2026-113470)

  - 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. (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. (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. (CVE-2026-113868)

  - When Thunderbird asked for a security device password (for example a smartcard PIN or the Primary     Password) while decrypting an S/MIME message, the message load could finish or be cancelled while the     prompt was open. This freed the message decoder while it was still in use, causing a use-after-free and a     potentially exploitable crash. (CVE-2026-113869)

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 158.0.1. It is, therefore, affected by multiple vulnerabilities as referenced in the mfsa2026-114 advisory.

  - Mozilla blocked compromised intermediate eMudhra certificates via OneCRL on the 17th of October which was     distributed to clients via RemoteSettings the same day. This update contains the updated OneCRL block     list, ensuring clients will block the compromised certificates even if RemoteSettings is disabled by     policy or otherwise unavailable in the user's network environment. (CVE-2026-113470)

  - 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. (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. (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. (CVE-2026-113868)

  - When Thunderbird asked for a security device password (for example a smartcard PIN or the Primary     Password) while decrypting an S/MIME message, the message load could finish or be cancelled while the     prompt was open. This freed the message decoder while it was still in use, causing a use-after-free and a     potentially exploitable crash. (CVE-2026-113869)

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.

  - 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)

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

ID	Name	Product	Family	Type	Severity
377000	AlmaLinux 9.2 [TuxCare] Security Update: thunderbird Multiple Vulnerabilities (ALMALINUX9.2:CLSA-2026:1793952112)	Nessus	Alma Linux Local Security Checks	Local	critical
374387	Amazon Linux 2 : thunderbird (ALAS-2026-4057)	Nessus	Amazon Linux Local Security Checks	Local	high
372151	Debian dla-4863 : thunderbird - security update	Nessus	Debian Local Security Checks	Local	critical
369496	Mozilla Thunderbird < 153.5.1	Nessus	Windows	Local	critical
369495	Mozilla Thunderbird < 153.5.1	Nessus	MacOS X Local Security Checks	Local	critical
369077	Mozilla Thunderbird < 158.0.1	Nessus	Windows	Local	critical
369076	Mozilla Thunderbird < 158.0.1	Nessus	MacOS X Local Security Checks	Local	critical
369006	Linux Distros Unpatched Vulnerability : CVE-2026-113867	Nessus	Misc.	Local	critical

Detections

Analytics

CVE-2026-113867

critical

Tenable Plugins

critical

high

critical

critical

critical

critical

critical

critical