The version of Firefox ESR installed on the remote Windows host is prior to 140.8. It is, therefore, affected by multiple vulnerabilities as referenced in the mfsa2026-15 advisory.

  - Memory safety bugs present in Firefox ESR 115.32, Firefox ESR 140.7, Thunderbird ESR 140.7, Firefox 147     and Thunderbird 147. Some of these bugs showed evidence of memory corruption and we presume that with     enough effort some of these could have been exploited to run arbitrary code. (CVE-2026-2793)

  - Sandbox escape due to incorrect boundary conditions in the DOM: Core & HTML component. This vulnerability     affects Firefox < 148, Firefox ESR < 115.33, Firefox ESR < 140.8, Thunderbird < 148, and Thunderbird <     140.8. (CVE-2026-2778)

  - Incorrect boundary conditions in the WebRTC: Audio/Video component. This vulnerability affects Firefox <     148, Firefox ESR < 115.33, Firefox ESR < 140.8, Thunderbird < 148, and Thunderbird < 140.8.
    (CVE-2026-2757)

  - Use-after-free in the JavaScript: GC component. This vulnerability affects Firefox < 148, Firefox ESR <     115.33, Firefox ESR < 140.8, Thunderbird < 148, and Thunderbird < 140.8. (CVE-2026-2758)

  - Incorrect boundary conditions in the Graphics: ImageLib component. This vulnerability affects Firefox <     148, Firefox ESR < 115.33, Firefox ESR < 140.8, Thunderbird < 148, and Thunderbird < 140.8.
    (CVE-2026-2759)

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 Firefox ESR installed on the remote macOS or Mac OS X host is prior to 140.8. It is, therefore, affected by multiple vulnerabilities as referenced in the mfsa2026-15 advisory.

  - Memory safety bugs present in Firefox ESR 115.32, Firefox ESR 140.7, Thunderbird ESR 140.7, Firefox 147     and Thunderbird 147. Some of these bugs showed evidence of memory corruption and we presume that with     enough effort some of these could have been exploited to run arbitrary code. (CVE-2026-2793)

  - Sandbox escape due to incorrect boundary conditions in the DOM: Core & HTML component. This vulnerability     affects Firefox < 148, Firefox ESR < 115.33, Firefox ESR < 140.8, Thunderbird < 148, and Thunderbird <     140.8. (CVE-2026-2778)

  - Incorrect boundary conditions in the WebRTC: Audio/Video component. This vulnerability affects Firefox <     148, Firefox ESR < 115.33, Firefox ESR < 140.8, Thunderbird < 148, and Thunderbird < 140.8.
    (CVE-2026-2757)

  - Use-after-free in the JavaScript: GC component. This vulnerability affects Firefox < 148, Firefox ESR <     115.33, Firefox ESR < 140.8, Thunderbird < 148, and Thunderbird < 140.8. (CVE-2026-2758)

  - Incorrect boundary conditions in the Graphics: ImageLib component. This vulnerability affects Firefox <     148, Firefox ESR < 115.33, Firefox ESR < 140.8, Thunderbird < 148, and Thunderbird < 140.8.
    (CVE-2026-2759)

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

The remote AlmaLinux 9 host has packages installed that are affected by multiple vulnerabilities as referenced in the ALSA-2026:3339 advisory.

    * libvpx: Heap buffer overflow in libvpx (CVE-2026-2447)
      * firefox: Invalid pointer in the JavaScript Engine component (CVE-2026-2785)
      * firefox: Memory safety bugs fixed in Firefox ESR 115.33, Firefox ESR 140.8, Thunderbird ESR 140.8,     Firefox 148 and Thunderbird 148 (CVE-2026-2793)
      * firefox: Undefined behavior in the DOM: Core & HTML component (CVE-2026-2771)
      * firefox: Integer overflow in the Audio/Video component (CVE-2026-2774)
      * firefox: Sandbox escape due to incorrect boundary conditions in the Telemetry component in External     Software (CVE-2026-2776)
      * firefox: Integer overflow in the Libraries component in NSS (CVE-2026-2781)
      * firefox: Use-after-free in the JavaScript Engine: JIT component (CVE-2026-2766)
      * firefox: Use-after-free in the Storage: IndexedDB component (CVE-2026-2769)
      * firefox: Use-after-free in the DOM: Window and Location component (CVE-2026-2787)
      * firefox: Sandbox escape in the Storage: IndexedDB component (CVE-2026-2768)
      * firefox: Information disclosure due to JIT miscompilation in the JavaScript Engine: JIT component     (CVE-2026-2783)
      * firefox: Incorrect boundary conditions in the Audio/Video: GMP component (CVE-2026-2788)
      * firefox: Mitigation bypass in the DOM: Security component (CVE-2026-2784)
      * firefox: Incorrect boundary conditions in the Graphics: ImageLib component (CVE-2026-2759)
      * firefox: Integer overflow in the JavaScript: Standard Library component (CVE-2026-2762)
      * firefox: Sandbox escape in the Graphics: WebRender component (CVE-2026-2761)
      * firefox: Privilege escalation in the Messaging System component (CVE-2026-2777)
      * firefox: Same-origin policy bypass in the Networking: JAR component (CVE-2026-2790)
      * firefox: Mitigation bypass in the DOM: HTML Parser component (CVE-2026-2775)
      * firefox: Use-after-free in the JavaScript Engine component (CVE-2026-2763)
      * firefox: Memory safety bugs fixed in Firefox ESR 140.8, Thunderbird ESR 140.8, Firefox 148 and     Thunderbird 148 (CVE-2026-2792)
      * firefox: Incorrect boundary conditions in the Web Audio component (CVE-2026-2773)
      * firefox: Use-after-free in the JavaScript Engine component (CVE-2026-2786)
      * firefox: Use-after-free in the Graphics: ImageLib component (CVE-2026-2789)
      * firefox: thunderbird: Incorrect boundary conditions in the WebRTC: Audio/Video component     (CVE-2026-2757)
      * firefox: Sandbox escape due to incorrect boundary conditions in the Graphics: WebRender component     (CVE-2026-2760)
      * firefox: Use-after-free in the Audio/Video: Playback component (CVE-2026-2772)
      * firefox: Incorrect boundary conditions in the Networking: JAR component (CVE-2026-2779)
      * firefox: Use-after-free in the JavaScript: WebAssembly component (CVE-2026-2767)
      * firefox: JIT miscompilation, use-after-free in the JavaScript Engine: JIT component (CVE-2026-2764)
      * firefox: Privilege escalation in the Netmonitor component (CVE-2026-2782)
      * firefox: Use-after-free in the JavaScript Engine component (CVE-2026-2765)
      * firefox: Privilege escalation in the Netmonitor component (CVE-2026-2780)
      * firefox: Sandbox escape due to incorrect boundary conditions in the DOM: Core & HTML component     (CVE-2026-2778)
      * firefox: Use-after-free in the JavaScript: GC component (CVE-2026-2758)
      * firefox: Mitigation bypass in the Networking: Cache component (CVE-2026-2791)
      * firefox: Use-after-free in the DOM: Bindings (WebIDL) component (CVE-2026-2770)

Tenable has extracted the preceding description block directly from the AlmaLinux 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 Redhat Enterprise Linux 8 host has a package installed that is affected by multiple vulnerabilities as referenced in the RHSA-2026:3492 advisory.

    Mozilla Firefox is an open-source web browser, designed for standards compliance, performance, and     portability.

    Security Fix(es):

    * libvpx: Heap buffer overflow in libvpx (CVE-2026-2447)

    * firefox: Invalid pointer in the JavaScript Engine component (CVE-2026-2785)

    * firefox: Memory safety bugs fixed in Firefox ESR 115.33, Firefox ESR 140.8, Thunderbird ESR 140.8,     Firefox 148 and Thunderbird 148 (CVE-2026-2793)

    * firefox: Undefined behavior in the DOM: Core & HTML component (CVE-2026-2771)

    * firefox: Integer overflow in the Audio/Video component (CVE-2026-2774)

    * firefox: Sandbox escape due to incorrect boundary conditions in the Telemetry component in External     Software (CVE-2026-2776)

    * firefox: Integer overflow in the Libraries component in NSS (CVE-2026-2781)

    * firefox: Use-after-free in the JavaScript Engine: JIT component (CVE-2026-2766)

    * firefox: Use-after-free in the Storage: IndexedDB component (CVE-2026-2769)

    * firefox: Use-after-free in the DOM: Window and Location component (CVE-2026-2787)

    * firefox: Sandbox escape in the Storage: IndexedDB component (CVE-2026-2768)

    * firefox: Information disclosure due to JIT miscompilation in the JavaScript Engine: JIT component     (CVE-2026-2783)

    * firefox: Incorrect boundary conditions in the Audio/Video: GMP component (CVE-2026-2788)

    * firefox: Mitigation bypass in the DOM: Security component (CVE-2026-2784)

    * firefox: Incorrect boundary conditions in the Graphics: ImageLib component (CVE-2026-2759)

    * firefox: Integer overflow in the JavaScript: Standard Library component (CVE-2026-2762)

    * firefox: Sandbox escape in the Graphics: WebRender component (CVE-2026-2761)

    * firefox: Privilege escalation in the Messaging System component (CVE-2026-2777)

    * firefox: Same-origin policy bypass in the Networking: JAR component (CVE-2026-2790)

    * firefox: Mitigation bypass in the DOM: HTML Parser component (CVE-2026-2775)

    * firefox: Use-after-free in the JavaScript Engine component (CVE-2026-2763)

    * firefox: Memory safety bugs fixed in Firefox ESR 140.8, Thunderbird ESR 140.8, Firefox 148 and     Thunderbird 148 (CVE-2026-2792)

    * firefox: Incorrect boundary conditions in the Web Audio component (CVE-2026-2773)

    * firefox: Use-after-free in the JavaScript Engine component (CVE-2026-2786)

    * firefox: Use-after-free in the Graphics: ImageLib component (CVE-2026-2789)

    * firefox: thunderbird: Incorrect boundary conditions in the WebRTC: Audio/Video component (CVE-2026-2757)

    * firefox: Sandbox escape due to incorrect boundary conditions in the Graphics: WebRender component     (CVE-2026-2760)

    * firefox: Use-after-free in the Audio/Video: Playback component (CVE-2026-2772)

    * firefox: Incorrect boundary conditions in the Networking: JAR component (CVE-2026-2779)

    * firefox: Use-after-free in the JavaScript: WebAssembly component (CVE-2026-2767)

    * firefox: JIT miscompilation, use-after-free in the JavaScript Engine: JIT component (CVE-2026-2764)

    * firefox: Privilege escalation in the Netmonitor component (CVE-2026-2782)

    * firefox: Use-after-free in the JavaScript Engine component (CVE-2026-2765)

    * firefox: Privilege escalation in the Netmonitor component (CVE-2026-2780)

    * firefox: Sandbox escape due to incorrect boundary conditions in the DOM: Core & HTML component     (CVE-2026-2778)

    * firefox: Use-after-free in the JavaScript: GC component (CVE-2026-2758)

    * firefox: Mitigation bypass in the Networking: Cache component (CVE-2026-2791)

    * firefox: Use-after-free in the DOM: Bindings (WebIDL) component (CVE-2026-2770)

    For more details about the security issue(s), including the impact, a CVSS score, acknowledgments, and     other related information, refer to the CVE page(s) listed in the References section.

Tenable has extracted the preceding description block directly from the Red Hat Enterprise Linux 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 RockyLinux 9 host has packages installed that are affected by multiple vulnerabilities as referenced in the RLSA-2026:3516 advisory.

    * libvpx: Heap buffer overflow in libvpx (CVE-2026-2447)

    * firefox: Invalid pointer in the JavaScript Engine component (CVE-2026-2785)

    * firefox: Memory safety bugs fixed in Firefox ESR 115.33, Firefox ESR 140.8, Thunderbird ESR 140.8,     Firefox 148 and Thunderbird 148 (CVE-2026-2793)

    * firefox: Undefined behavior in the DOM: Core & HTML component (CVE-2026-2771)

    * firefox: Integer overflow in the Audio/Video component (CVE-2026-2774)

    * firefox: Sandbox escape due to incorrect boundary conditions in the Telemetry component in External     Software (CVE-2026-2776)

    * firefox: Integer overflow in the Libraries component in NSS (CVE-2026-2781)

    * firefox: Use-after-free in the JavaScript Engine: JIT component (CVE-2026-2766)

    * firefox: Use-after-free in the Storage: IndexedDB component (CVE-2026-2769)

    * firefox: Use-after-free in the DOM: Window and Location component (CVE-2026-2787)

    * firefox: Sandbox escape in the Storage: IndexedDB component (CVE-2026-2768)

    * firefox: Information disclosure due to JIT miscompilation in the JavaScript Engine: JIT component     (CVE-2026-2783)

    * firefox: Incorrect boundary conditions in the Audio/Video: GMP component (CVE-2026-2788)

    * firefox: Mitigation bypass in the DOM: Security component (CVE-2026-2784)

    * firefox: Incorrect boundary conditions in the Graphics: ImageLib component (CVE-2026-2759)

    * firefox: Integer overflow in the JavaScript: Standard Library component (CVE-2026-2762)

    * firefox: Sandbox escape in the Graphics: WebRender component (CVE-2026-2761)

    * firefox: Privilege escalation in the Messaging System component (CVE-2026-2777)

    * firefox: Same-origin policy bypass in the Networking: JAR component (CVE-2026-2790)

    * firefox: Mitigation bypass in the DOM: HTML Parser component (CVE-2026-2775)

    * firefox: Use-after-free in the JavaScript Engine component (CVE-2026-2763)

    * firefox: Memory safety bugs fixed in Firefox ESR 140.8, Thunderbird ESR 140.8, Firefox 148 and     Thunderbird 148 (CVE-2026-2792)

    * firefox: Incorrect boundary conditions in the Web Audio component (CVE-2026-2773)

    * firefox: Use-after-free in the JavaScript Engine component (CVE-2026-2786)

    * firefox: Use-after-free in the Graphics: ImageLib component (CVE-2026-2789)

    * firefox: thunderbird: Incorrect boundary conditions in the WebRTC: Audio/Video component (CVE-2026-2757)

    * firefox: Sandbox escape due to incorrect boundary conditions in the Graphics: WebRender component     (CVE-2026-2760)

    * firefox: Use-after-free in the Audio/Video: Playback component (CVE-2026-2772)

    * firefox: Incorrect boundary conditions in the Networking: JAR component (CVE-2026-2779)

    * firefox: Use-after-free in the JavaScript: WebAssembly component (CVE-2026-2767)

    * firefox: JIT miscompilation, use-after-free in the JavaScript Engine: JIT component (CVE-2026-2764)

    * firefox: Privilege escalation in the Netmonitor component (CVE-2026-2782)

    * firefox: Use-after-free in the JavaScript Engine component (CVE-2026-2765)

    * firefox: Privilege escalation in the Netmonitor component (CVE-2026-2780)

    * firefox: Sandbox escape due to incorrect boundary conditions in the DOM: Core & HTML component     (CVE-2026-2778)

    * firefox: Use-after-free in the JavaScript: GC component (CVE-2026-2758)

    * firefox: Mitigation bypass in the Networking: Cache component (CVE-2026-2791)

    * firefox: Use-after-free in the DOM: Bindings (WebIDL) component (CVE-2026-2770)

Tenable has extracted the preceding description block directly from the RockyLinux 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 Oracle Linux 10 host has a package installed that is affected by multiple vulnerabilities as referenced in the ELSA-2026-3517 advisory.

    [140.8.0-2.0.1]
    - Add Oracle prefs

    [140.8.0-2]
    - Update to 140.8.0 ESR

Tenable has extracted the preceding description block directly from the Oracle Linux 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 Redhat Enterprise Linux 9 host has a package installed that is affected by multiple vulnerabilities as referenced in the RHSA-2026:3982 advisory.

    Mozilla Thunderbird is a standalone mail and newsgroup client.

    Security Fix(es):

    * libvpx: Heap buffer overflow in libvpx (CVE-2026-2447)

    * firefox: Invalid pointer in the JavaScript Engine component (CVE-2026-2785)

    * firefox: Memory safety bugs fixed in Firefox ESR 115.33, Firefox ESR 140.8, Thunderbird ESR 140.8,     Firefox 148 and Thunderbird 148 (CVE-2026-2793)

    * firefox: Undefined behavior in the DOM: Core & HTML component (CVE-2026-2771)

    * firefox: Integer overflow in the Audio/Video component (CVE-2026-2774)

    * firefox: Sandbox escape due to incorrect boundary conditions in the Telemetry component in External     Software (CVE-2026-2776)

    * firefox: Integer overflow in the Libraries component in NSS (CVE-2026-2781)

    * firefox: Use-after-free in the JavaScript Engine: JIT component (CVE-2026-2766)

    * firefox: Use-after-free in the Storage: IndexedDB component (CVE-2026-2769)

    * firefox: Use-after-free in the DOM: Window and Location component (CVE-2026-2787)

    * firefox: Sandbox escape in the Storage: IndexedDB component (CVE-2026-2768)

    * firefox: Information disclosure due to JIT miscompilation in the JavaScript Engine: JIT component     (CVE-2026-2783)

    * firefox: Incorrect boundary conditions in the Audio/Video: GMP component (CVE-2026-2788)

    * firefox: Mitigation bypass in the DOM: Security component (CVE-2026-2784)

    * firefox: Incorrect boundary conditions in the Graphics: ImageLib component (CVE-2026-2759)

    * firefox: Integer overflow in the JavaScript: Standard Library component (CVE-2026-2762)

    * firefox: Sandbox escape in the Graphics: WebRender component (CVE-2026-2761)

    * firefox: Privilege escalation in the Messaging System component (CVE-2026-2777)

    * firefox: Same-origin policy bypass in the Networking: JAR component (CVE-2026-2790)

    * firefox: Mitigation bypass in the DOM: HTML Parser component (CVE-2026-2775)

    * firefox: Use-after-free in the JavaScript Engine component (CVE-2026-2763)

    * firefox: Memory safety bugs fixed in Firefox ESR 140.8, Thunderbird ESR 140.8, Firefox 148 and     Thunderbird 148 (CVE-2026-2792)

    * firefox: Incorrect boundary conditions in the Web Audio component (CVE-2026-2773)

    * firefox: Use-after-free in the JavaScript Engine component (CVE-2026-2786)

    * firefox: Use-after-free in the Graphics: ImageLib component (CVE-2026-2789)

    * firefox: thunderbird: Incorrect boundary conditions in the WebRTC: Audio/Video component (CVE-2026-2757)

    * firefox: Sandbox escape due to incorrect boundary conditions in the Graphics: WebRender component     (CVE-2026-2760)

    * firefox: Use-after-free in the Audio/Video: Playback component (CVE-2026-2772)

    * firefox: Incorrect boundary conditions in the Networking: JAR component (CVE-2026-2779)

    * firefox: Use-after-free in the JavaScript: WebAssembly component (CVE-2026-2767)

    * firefox: JIT miscompilation, use-after-free in the JavaScript Engine: JIT component (CVE-2026-2764)

    * firefox: Privilege escalation in the Netmonitor component (CVE-2026-2782)

    * firefox: Use-after-free in the JavaScript Engine component (CVE-2026-2765)

    * firefox: Privilege escalation in the Netmonitor component (CVE-2026-2780)

    * firefox: Sandbox escape due to incorrect boundary conditions in the DOM: Core & HTML component     (CVE-2026-2778)

    * firefox: Use-after-free in the JavaScript: GC component (CVE-2026-2758)

    * firefox: Mitigation bypass in the Networking: Cache component (CVE-2026-2791)

    * firefox: Use-after-free in the DOM: Bindings (WebIDL) component (CVE-2026-2770)

    For more details about the security issue(s), including the impact, a CVSS score, acknowledgments, and     other related information, refer to the CVE page(s) listed in the References section.

Tenable has extracted the preceding description block directly from the Red Hat Enterprise Linux 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-2026:1785560172 advisory.

  - Certificate OCSP revocation status was not checked when verifying S/Mime signatures. Mail signed with a     revoked certificate would be displayed as having a valid signature. Thunderbird versions from 68 to     102.7.0 were affected by this bug. This vulnerability affects Thunderbird < 102.7.1. (CVE-2023-0430)

  - If a MIME email combines OpenPGP and OpenPGP MIME data in a certain way Thunderbird repeatedly attempts to     process and display the message, which could cause Thunderbird's user interface to lock up and no longer     respond to the user's actions. An attacker could send a crafted message with this structure to attempt a     DoS attack. This vulnerability affects Thunderbird < 102.8. (CVE-2023-0616)

  - Unexpected data returned from the Safe Browsing API could have led to memory corruption and a potentially     exploitable crash. This vulnerability affects Thunderbird < 102.10 and Firefox ESR < 102.10.
    (CVE-2023-1945)

  - Due to the Firefox GTK wrapper code's use of text/plain for drag data and GTK treating all text/plain     MIMEs containing file URLs as being dragged a website could arbitrarily read a file via a call to     `DataTransfer.setData`. This vulnerability affects Firefox < 109, Firefox ESR < 102.7, and Thunderbird <     102.7. (CVE-2023-23598)

  - When importing a SPKI RSA public key as ECDSA P-256, the key would be handled incorrectly causing the tab     to crash. This vulnerability affects Firefox < 110, Thunderbird < 102.8, and Firefox ESR < 102.8.
    (CVE-2023-25742)

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	Published	Updated	Severity
299869	Mozilla Firefox ESR < 140.8	Nessus	Windows	2/24/2026	4/30/2026	critical
299870	Mozilla Firefox ESR < 140.8	Nessus	MacOS X Local Security Checks	2/24/2026	4/30/2026	critical
300028	AlmaLinux 9 : firefox (ALSA-2026:3339)	Nessus	Alma Linux Local Security Checks	2/26/2026	4/30/2026	critical
300216	RHEL 8 : firefox (RHSA-2026:3492)	Nessus	Red Hat Local Security Checks	3/2/2026	4/30/2026	critical
300654	RockyLinux 9 : thunderbird (RLSA-2026:3516)	Nessus	Rocky Linux Local Security Checks	3/4/2026	3/4/2026	critical
300944	Oracle Linux 10 : thunderbird (ELSA-2026-3517)	Nessus	Oracle Linux Local Security Checks	3/5/2026	4/30/2026	critical
301493	RHEL 9 : thunderbird (RHSA-2026:3982)	Nessus	Red Hat Local Security Checks	3/9/2026	3/9/2026	critical
360088	AlmaLinux 9.2 [TuxCare] Security Update: thunderbird Multiple Vulnerabilities (ALMALINUX9.2:CLSA-2026:1785560172)	Nessus	Alma Linux Local Security Checks	10/1/2026	10/22/2026	critical

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