The code to parse MIME headers for display when forwarding a message (if the setting to view all headers was enabled) had an off-by-one error, allowing a single byte to be read from the memory after the buffer for the headers, and potentially crashing Thunderbird. This vulnerability was fixed in Thunderbird 153 and Thunderbird 140.13.

The version of Thunderbird installed on the remote Windows host is prior to 140.13. It is, therefore, affected by multiple vulnerabilities as referenced in the mfsa2026-72 advisory.

  - Memory safety bugs present in Thunderbird ESR 140.12 and Thunderbird 152. 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-2026-16360, CVE-2026-16412)

  - The code to parse MIME headers for display when forwarding a message (if the setting to view all headers     was enabled) had an off-by-one error, allowing a single byte to be read from the memory after the buffer     for the headers, and potentially crashing Thunderbird. (CVE-2026-14899)

  - We are aware that exploit code for this is public however we are not aware of any attacks in the wild     abusing this flaw. (CVE-2026-15718, CVE-2026-15719)

  - Same-origin policy bypass in the DOM: Navigation component. This vulnerability was fixed in Firefox 153,     Firefox ESR 115.38, Firefox ESR 140.13, Thunderbird 153, and Thunderbird 140.13. (CVE-2026-16349)

  - Incorrect boundary conditions in the Audio/Video: cubeb component. This vulnerability was fixed in Firefox     153, Firefox ESR 115.38, Firefox ESR 140.13, Thunderbird 153, and Thunderbird 140.13. (CVE-2026-16350)

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 153.0. It is, therefore, affected by multiple vulnerabilities as referenced in the mfsa2026-71 advisory.

  - Memory safety bugs present in Thunderbird ESR 140.12 and Thunderbird 152. 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-2026-16360, CVE-2026-16412)

  - Sandbox escape due to invalid pointer in the Disability Access APIs component. This vulnerability was     fixed in Firefox 153 and Thunderbird 153. (CVE-2026-16367)

  - The code to parse MIME headers for display when forwarding a message (if the setting to view all headers     was enabled) had an off-by-one error, allowing a single byte to be read from the memory after the buffer     for the headers, and potentially crashing Thunderbird. (CVE-2026-14899)

  - Same-origin policy bypass in the DOM: Navigation component. This vulnerability was fixed in Firefox 153,     Firefox ESR 115.38, Firefox ESR 140.13, Thunderbird 153, and Thunderbird 140.13. (CVE-2026-16349)

  - Incorrect boundary conditions in the Audio/Video: cubeb component. This vulnerability was fixed in Firefox     153, Firefox ESR 115.38, Firefox ESR 140.13, Thunderbird 153, and Thunderbird 140.13. (CVE-2026-16350)

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 140.13. It is, therefore, affected by multiple vulnerabilities as referenced in the mfsa2026-72 advisory.

  - Memory safety bugs present in Thunderbird ESR 140.12 and Thunderbird 152. 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-2026-16360, CVE-2026-16412)

  - The code to parse MIME headers for display when forwarding a message (if the setting to view all headers     was enabled) had an off-by-one error, allowing a single byte to be read from the memory after the buffer     for the headers, and potentially crashing Thunderbird. (CVE-2026-14899)

  - We are aware that exploit code for this is public however we are not aware of any attacks in the wild     abusing this flaw. (CVE-2026-15718, CVE-2026-15719)

  - Same-origin policy bypass in the DOM: Navigation component. This vulnerability was fixed in Firefox 153,     Firefox ESR 115.38, Firefox ESR 140.13, Thunderbird 153, and Thunderbird 140.13. (CVE-2026-16349)

  - Incorrect boundary conditions in the Audio/Video: cubeb component. This vulnerability was fixed in Firefox     153, Firefox ESR 115.38, Firefox ESR 140.13, Thunderbird 153, and Thunderbird 140.13. (CVE-2026-16350)

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 153.0. It is, therefore, affected by multiple vulnerabilities as referenced in the mfsa2026-71 advisory.

  - Memory safety bugs present in Thunderbird ESR 140.12 and Thunderbird 152. 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-2026-16360, CVE-2026-16412)

  - Sandbox escape due to invalid pointer in the Disability Access APIs component. This vulnerability was     fixed in Firefox 153 and Thunderbird 153. (CVE-2026-16367)

  - The code to parse MIME headers for display when forwarding a message (if the setting to view all headers     was enabled) had an off-by-one error, allowing a single byte to be read from the memory after the buffer     for the headers, and potentially crashing Thunderbird. (CVE-2026-14899)

  - Same-origin policy bypass in the DOM: Navigation component. This vulnerability was fixed in Firefox 153,     Firefox ESR 115.38, Firefox ESR 140.13, Thunderbird 153, and Thunderbird 140.13. (CVE-2026-16349)

  - Incorrect boundary conditions in the Audio/Video: cubeb component. This vulnerability was fixed in Firefox     153, Firefox ESR 115.38, Firefox ESR 140.13, Thunderbird 153, and Thunderbird 140.13. (CVE-2026-16350)

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
329091	Mozilla Thunderbird < 140.13	Nessus	Windows	critical
329090	Mozilla Thunderbird < 153.0	Nessus	MacOS X Local Security Checks	critical
329089	Mozilla Thunderbird < 140.13	Nessus	MacOS X Local Security Checks	critical
329088	Mozilla Thunderbird < 153.0	Nessus	Windows	critical

Detections

Analytics

CVE-2026-14899

high

Tenable Plugins

critical

critical

critical

critical