Mitigation bypass in the Networking: Cache component. This vulnerability affects Firefox < 148, Firefox ESR < 140.8, Thunderbird < 148, and Thunderbird < 140.8.

The remote Redhat Enterprise Linux 10 host has a package installed that is affected by multiple vulnerabilities as referenced in the RHSA-2026:3361 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 Linux/Unix host has one or more packages installed that are impacted by a vulnerability without a vendor supplied patch available.

  - Mitigation bypass in the Networking: Cache component. This vulnerability affects Firefox < 148, Firefox     ESR < 140.8, Thunderbird < 148, and Thunderbird < 140.8. (CVE-2026-2791)

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

The version of Thunderbird installed on the remote Windows host is prior to 140.8. It is, therefore, affected by multiple vulnerabilities as referenced in the mfsa2026-17 advisory.

  - Use-after-free in the Storage: IndexedDB component. This vulnerability affects Firefox < 148, Firefox ESR     < 115.33, Firefox ESR < 140.8, Thunderbird < 148, and Thunderbird < 140.8. (CVE-2026-2769)

  - 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)

  - Sandbox escape due to incorrect boundary conditions in the Graphics: WebRender component. This     vulnerability affects Firefox < 148, Firefox ESR < 115.33, Firefox ESR < 140.8, Thunderbird < 148, and     Thunderbird < 140.8. (CVE-2026-2760)

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 148.0. It is, therefore, affected by multiple vulnerabilities as referenced in the mfsa2026-16 advisory.

  - Use-after-free in the Storage: IndexedDB component. This vulnerability affects Firefox < 148, Firefox ESR     < 115.33, Firefox ESR < 140.8, Thunderbird < 148, and Thunderbird < 140.8. (CVE-2026-2769)

  - Use-after-free in the DOM: Core & HTML component. This vulnerability affects Firefox < 148 and Thunderbird     < 148. (CVE-2026-2798, CVE-2026-2799)

  - 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 Thunderbird 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 mfsa2026-17 advisory.

  - Use-after-free in the Storage: IndexedDB component. This vulnerability affects Firefox < 148, Firefox ESR     < 115.33, Firefox ESR < 140.8, Thunderbird < 148, and Thunderbird < 140.8. (CVE-2026-2769)

  - 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)

  - Sandbox escape due to incorrect boundary conditions in the Graphics: WebRender component. This     vulnerability affects Firefox < 148, Firefox ESR < 115.33, Firefox ESR < 140.8, Thunderbird < 148, and     Thunderbird < 140.8. (CVE-2026-2760)

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 148.0. It is, therefore, affected by multiple vulnerabilities as referenced in the mfsa2026-16 advisory.

  - Use-after-free in the Storage: IndexedDB component. This vulnerability affects Firefox < 148, Firefox ESR     < 115.33, Firefox ESR < 140.8, Thunderbird < 148, and Thunderbird < 140.8. (CVE-2026-2769)

  - Use-after-free in the DOM: Core & HTML component. This vulnerability affects Firefox < 148 and Thunderbird     < 148. (CVE-2026-2798, CVE-2026-2799)

  - 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)

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

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

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

  - Sandbox escape due to incorrect boundary conditions in the Graphics: WebRender component. This     vulnerability affects Firefox < 148, Firefox ESR < 115.33, and Firefox ESR < 140.8. (CVE-2026-2760)

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 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)

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

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

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

  - Sandbox escape due to incorrect boundary conditions in the Graphics: WebRender component. This     vulnerability affects Firefox < 148, Firefox ESR < 115.33, and Firefox ESR < 140.8. (CVE-2026-2760)

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 installed on the remote macOS or Mac OS X host is prior to 148.0. It is, therefore, affected by multiple vulnerabilities as referenced in the mfsa2026-13 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)

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

  - Information disclosure due to uninitialized memory in Firefox and Firefox Focus for Android. This     vulnerability affects Firefox < 148. (CVE-2026-2794)

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

  - Incorrect boundary conditions in the Graphics: ImageLib component. This vulnerability affects Firefox <     148, Firefox ESR < 115.33, and Firefox ESR < 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 installed on the remote Windows host is prior to 148.0. It is, therefore, affected by multiple vulnerabilities as referenced in the mfsa2026-13 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)

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

  - Information disclosure due to uninitialized memory in Firefox and Firefox Focus for Android. This     vulnerability affects Firefox < 148. (CVE-2026-2794)

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

  - Incorrect boundary conditions in the Graphics: ImageLib component. This vulnerability affects Firefox <     148, Firefox ESR < 115.33, and Firefox ESR < 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.

ID	Name	Product	Family	Severity
299964	RHEL 10 : firefox (RHSA-2026:3361)	Nessus	Red Hat Local Security Checks	critical
299908	Linux Distros Unpatched Vulnerability : CVE-2026-2791	Nessus	Misc.	high
299892	Mozilla Thunderbird < 140.8	Nessus	Windows	high
299891	Mozilla Thunderbird < 148.0	Nessus	Windows	high
299890	Mozilla Thunderbird < 140.8	Nessus	MacOS X Local Security Checks	high
299889	Mozilla Thunderbird < 148.0	Nessus	MacOS X Local Security Checks	high
299870	Mozilla Firefox ESR < 140.8	Nessus	MacOS X Local Security Checks	high
299869	Mozilla Firefox ESR < 140.8	Nessus	Windows	high
299866	Mozilla Firefox < 148.0	Nessus	MacOS X Local Security Checks	high
299865	Mozilla Firefox < 148.0	Nessus	Windows	high

Detections

Analytics

CVE-2026-2791

low

Tenable Plugins

critical

high

high

high

high

high

high

high

high

high