Use-after-free in the JavaScript Engine component. This vulnerability affects Firefox < 148, Firefox ESR < 140.8, Thunderbird < 148, and Thunderbird < 140.8.

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

  - Use-after-free in the JavaScript Engine component. This vulnerability affects Firefox < 148, Firefox ESR <     140.8, Thunderbird < 148, and Thunderbird < 140.8. (CVE-2026-2786)

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
299915	Linux Distros Unpatched Vulnerability : CVE-2026-2786	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-2026-2786

high

Tenable Plugins

high

high

high

high

high

high

high

high

high