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.

slackware SSA:2026-273-02: [slackware-security] mozilla-thunderbird (SSA:2026-273-02)

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
358366	Linux Distros Unpatched Vulnerability : CVE-2026-103500	Nessus	Misc.	Local	high
353287	Mozilla Thunderbird < 157.0	Nessus	MacOS X Local Security Checks	Local	critical
353286	Mozilla Thunderbird < 157.0	Nessus	Windows	Local	critical
353285	Mozilla Thunderbird < 153.4	Nessus	MacOS X Local Security Checks	Local	critical
353284	Mozilla Thunderbird < 153.4	Nessus	Windows	Local	critical
353283	Mozilla Thunderbird < 140.17	Nessus	MacOS X Local Security Checks	Local	critical
353282	Mozilla Thunderbird < 140.17	Nessus	Windows	Local	critical

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