The version of Firefox installed on the remote Windows host is prior to 150.0. It is, therefore, affected by multiple vulnerabilities as referenced in the mfsa2026-30 advisory.

  - Memory safety bugs present in Firefox ESR 140.9, Thunderbird ESR 140.9, Firefox 149 and Thunderbird 149.
    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-2026-6786)

  - Memory safety bugs present in Firefox 149 and Thunderbird 149. 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-2026-6784)

  - Memory safety bugs present in Firefox ESR 115.34, Firefox ESR 140.9, Thunderbird ESR 140.9, Firefox 149     and Thunderbird 149. 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-2026-6785)

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 150.0. It is, therefore, affected by multiple vulnerabilities as referenced in the mfsa2026-33 advisory.

  - Incorrect boundary conditions, integer overflow in the Audio/Video: Playback component. This vulnerability     was fixed in Firefox 150 and Thunderbird 150. (CVE-2026-6783)

  - Use-after-free in the DOM: Core & HTML component. This vulnerability was fixed in Firefox 150, Firefox ESR     115.35, Firefox ESR 140.10, Thunderbird 150, and Thunderbird 140.10. (CVE-2026-6746)

  - Use-after-free in the WebRTC component. This vulnerability was fixed in Firefox 150, Firefox ESR 140.10,     Thunderbird 150, and Thunderbird 140.10. (CVE-2026-6747)

  - Uninitialized memory in the Audio/Video: Web Codecs component. This vulnerability was fixed in Firefox     150, Firefox ESR 140.10, Thunderbird 150, and Thunderbird 140.10. (CVE-2026-6748, CVE-2026-6751)

  - Information disclosure due to uninitialized memory in the Graphics: Canvas2D component. This vulnerability     was fixed in Firefox 150, Firefox ESR 115.35, Firefox ESR 140.10, Thunderbird 150, and Thunderbird 140.10.
    (CVE-2026-6749)

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.

  - Use-after-free in the JavaScript: WebAssembly component. This vulnerability was fixed in Firefox 150 and     Thunderbird 150. (CVE-2026-6758)

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

The version of Firefox installed on the remote macOS or Mac OS X host is prior to 150.0. It is, therefore, affected by multiple vulnerabilities as referenced in the mfsa2026-30 advisory.

  - Memory safety bugs present in Firefox ESR 140.9, Thunderbird ESR 140.9, Firefox 149 and Thunderbird 149.
    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-2026-6786)

  - Memory safety bugs present in Firefox 149 and Thunderbird 149. 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-2026-6784)

  - Memory safety bugs present in Firefox ESR 115.34, Firefox ESR 140.9, Thunderbird ESR 140.9, Firefox 149     and Thunderbird 149. 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-2026-6785)

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 150.0. It is, therefore, affected by multiple vulnerabilities as referenced in the mfsa2026-33 advisory.

  - Incorrect boundary conditions, integer overflow in the Audio/Video: Playback component. This vulnerability     was fixed in Firefox 150 and Thunderbird 150. (CVE-2026-6783)

  - Use-after-free in the DOM: Core & HTML component. This vulnerability was fixed in Firefox 150, Firefox ESR     115.35, Firefox ESR 140.10, Thunderbird 150, and Thunderbird 140.10. (CVE-2026-6746)

  - Use-after-free in the WebRTC component. This vulnerability was fixed in Firefox 150, Firefox ESR 140.10,     Thunderbird 150, and Thunderbird 140.10. (CVE-2026-6747)

  - Uninitialized memory in the Audio/Video: Web Codecs component. This vulnerability was fixed in Firefox     150, Firefox ESR 140.10, Thunderbird 150, and Thunderbird 140.10. (CVE-2026-6748, CVE-2026-6751)

  - Information disclosure due to uninitialized memory in the Graphics: Canvas2D component. This vulnerability     was fixed in Firefox 150, Firefox ESR 115.35, Firefox ESR 140.10, Thunderbird 150, and Thunderbird 140.10.
    (CVE-2026-6749)

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

The remote Fedora 44 host has packages installed that are affected by multiple vulnerabilities as referenced in the FEDORA-2026-fb08ad61f2 advisory.

    Update NSS to 3.122.1     Update to Firefox 150.0


    ----

    - New upstream release (149.0.2)

Tenable has extracted the preceding description block directly from the Fedora 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 version of FreeBSD installed on the remote host is prior to tested version. It is, therefore, affected by a vulnerability as referenced in the 6a439169-4305-11f1-a627-b42e991fc52e advisory.

    https://bugzilla.mozilla.org/show_bug.cgi?id=2013619 reports:
    Use-after-free in the JavaScript: WebAssembly component.

Tenable has extracted the preceding description block directly from the FreeBSD security advisory.

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

The remote Fedora 42 host has packages installed that are affected by multiple vulnerabilities as referenced in the FEDORA-2026-69538c9f7e advisory.

    Update NSS to 3.122.1     Update to Firefox 150.0

Tenable has extracted the preceding description block directly from the Fedora security advisory.

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
307899	Mozilla Firefox < 150.0	Nessus	Windows	4/21/2026	4/27/2026	medium
309098	Mozilla Thunderbird < 150.0	Nessus	MacOS X Local Security Checks	4/21/2026	4/29/2026	medium
310615	Linux Distros Unpatched Vulnerability : CVE-2026-6758	Nessus	Misc.	4/28/2026	4/28/2026	high
307895	Mozilla Firefox < 150.0	Nessus	MacOS X Local Security Checks	4/21/2026	4/27/2026	medium
309100	Mozilla Thunderbird < 150.0	Nessus	Windows	4/21/2026	4/29/2026	medium
310077	Fedora 44 : firefox / nss (2026-fb08ad61f2)	Nessus	Fedora Local Security Checks	4/24/2026	4/29/2026	medium
311026	FreeBSD : Mozilla -- Use-after-free (6a439169-4305-11f1-a627-b42e991fc52e)	Nessus	FreeBSD Local Security Checks	4/29/2026	4/29/2026	high
310573	Fedora 42 : firefox / nss (2026-69538c9f7e)	Nessus	Fedora Local Security Checks	4/28/2026	4/30/2026	medium

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