The version of Thunderbird installed on the remote macOS or Mac OS X host is prior to 140.14. It is, therefore, affected by multiple vulnerabilities as referenced in the mfsa2026-79 advisory.

  - Internally found bugs present in Thunderbird ESR 140.13, Thunderbird ESR 153.0 and Thunderbird 153. Some     of these bugs showed evidence of memory corruption or another security-relevant defect and we presume that     with enough effort some of these could have been exploited. (CVE-2026-74987, CVE-2026-74990)

  - Site isolation issue in the Graphics: CanvasWebGL component. This vulnerability was fixed in Firefox 154,     Firefox ESR 115.39, Firefox ESR 140.14, Firefox ESR 153.1, Thunderbird 154, Thunderbird 140.14, and     Thunderbird 153.1. (CVE-2026-74934)

  - Privilege escalation in the DOM: Networking component. This vulnerability was fixed in Firefox 154,     Firefox ESR 115.39, Firefox ESR 140.14, Firefox ESR 153.1, Thunderbird 154, Thunderbird 140.14, and     Thunderbird 153.1. (CVE-2026-74935)

  - Use-after-free in the JavaScript: WebAssembly component. This vulnerability was fixed in Firefox 154,     Firefox ESR 140.14, Firefox ESR 153.1, Thunderbird 154, Thunderbird 140.14, and Thunderbird 153.1.
    (CVE-2026-74936)

  - Privilege escalation in the DOM: Navigation component. This vulnerability was fixed in Firefox 154,     Firefox ESR 115.39, Firefox ESR 140.14, Firefox ESR 153.1, Thunderbird 154, Thunderbird 140.14, and     Thunderbird 153.1. (CVE-2026-74939)

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

The remote Debian 13 host has packages installed that are affected by multiple vulnerabilities as referenced in the dsa-6461 advisory.

    - -------------------------------------------------------------------------     Debian Security Advisory DSA-6461-1                   security@debian.org     https://www.debian.org/security/                       Moritz Muehlenhoff     August 23, 2026                       https://www.debian.org/security/faq
    - -------------------------------------------------------------------------

    Package        : thunderbird     CVE ID         : CVE-2026-74934 CVE-2026-74935 CVE-2026-74936 CVE-2026-74939                      CVE-2026-74940 CVE-2026-74941 CVE-2026-74942 CVE-2026-74943                      CVE-2026-74944 CVE-2026-74945 CVE-2026-74946 CVE-2026-74948                      CVE-2026-74949 CVE-2026-74953 CVE-2026-74957 CVE-2026-74959                      CVE-2026-74960 CVE-2026-74962 CVE-2026-74963 CVE-2026-74964                      CVE-2026-74965 CVE-2026-74967 CVE-2026-74969 CVE-2026-74971                      CVE-2026-74972 CVE-2026-74973 CVE-2026-74974 CVE-2026-74976                      CVE-2026-74983 CVE-2026-74987 CVE-2026-74990

    Multiple security issues were discovered in Thunderbird, which could     result in the execution of arbitrary code or information disclosure

    For the stable distribution (trixie), these problems have been fixed in     version 1:140.14.0esr-1~deb13u1.

    We recommend that you upgrade your thunderbird packages.

    For the detailed security status of thunderbird please refer to     its security tracker page at:
    https://security-tracker.debian.org/tracker/thunderbird

    Further information about Debian Security Advisories, how to apply     these updates to your system and frequently asked questions can be     found at: https://www.debian.org/security/

    Mailing list: debian-security-announce@lists.debian.org

Tenable has extracted the preceding description block directly from the Debian 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 remote Redhat Enterprise Linux 8 host has a package installed that is affected by multiple vulnerabilities as referenced in the RHSA-2026:58898 advisory.

    Mozilla Firefox is an open-source web browser, designed for standards compliance, performance, and     portability.

    Security Fix(es):

    * firefox: thunderbird: Mitigation bypass in the Data Loss Prevention component (CVE-2026-74983)

    * firefox: thunderbird: Site isolation issue in the Graphics: CanvasWebGL component (CVE-2026-74934)

    * firefox: thunderbird: Privilege escalation in the Networking: Cookies component (CVE-2026-74953)

    * firefox: thunderbird: Internally found bugs fixed in Firefox ESR 140.14, Firefox ESR 153.1 and Firefox     154 (CVE-2026-74987)

    * firefox: thunderbird: Information disclosure in the Graphics component (CVE-2026-74948)

    * firefox: thunderbird: Use-after-free in the Graphics: ImageLib component (CVE-2026-74943)

    * firefox: thunderbird: Information disclosure in the DOM: UI Events & Focus Handling component     (CVE-2026-74971)

    * firefox: thunderbird: Privilege escalation in the Graphics: CanvasWebGL component (CVE-2026-74941)

    * firefox: Privilege escalation in the Shell Integration component (CVE-2026-74965)

    * firefox: thunderbird: Privilege escalation due to incorrect boundary conditions in the Graphics:
    CanvasWebGL component (CVE-2026-74946)

    * firefox: Race condition, use-after-free in the Graphics component (CVE-2026-74973)

    * firefox: thunderbird: Privilege escalation due to use-after-free in the Graphics: Canvas2D component     (CVE-2026-74949)

    * firefox: thunderbird: Internally found bugs fixed in Firefox ESR 115.39, Firefox ESR 140.14, Firefox ESR     153.1 and Firefox 154 (CVE-2026-74990)

    * firefox: thunderbird: Use-after-free in the JavaScript: WebAssembly component (CVE-2026-74936)

    * firefox: thunderbird: Use-after-free in the Graphics: Text component (CVE-2026-74940)

    * firefox: thunderbird: Site isolation issue in the WebExtensions component (CVE-2026-74960)

    * firefox: thunderbird: Use-after-free in the Layout: Text and Fonts component (CVE-2026-74969)

    * firefox: thunderbird: Mitigation bypass in the Storage: Cache API component (CVE-2026-74959)

    * firefox: thunderbird: JIT miscompilation in the JavaScript Engine: JIT component (CVE-2026-74976)

    * firefox: thunderbird: Same-origin policy bypass in the Graphics: ImageLib component (CVE-2026-74974)

    * firefox: thunderbird: Mitigation bypass in the Safe Browsing component (CVE-2026-74957)

    * firefox: thunderbird: Same-origin policy bypass in the Audio/Video: Playback component (CVE-2026-74967)

    * firefox: Privilege escalation in the Remote Settings Client component (CVE-2026-74942)

    * firefox: thunderbird: Privilege escalation in the DOM: Navigation component (CVE-2026-74939)

    * firefox: thunderbird: Information disclosure in the DOM: Push Subscriptions component (CVE-2026-74972)

    * firefox: thunderbird: Information disclosure in the Graphics: Text component (CVE-2026-74945)

    * firefox: thunderbird: Same-origin policy bypass in the Networking: Cookies component (CVE-2026-74963)

    * firefox: thunderbird: Use-after-free in the DOM: Core & HTML component (CVE-2026-74944)

    * firefox: Integer overflow in the Graphics component (CVE-2026-74964)

    * firefox: Site isolation issue in the Networking: Cookies component (CVE-2026-74962)

    * firefox: thunderbird: Privilege escalation in the DOM: Networking component (CVE-2026-74935)

    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 remote Debian 11 / 12 host has packages installed that are affected by multiple vulnerabilities as referenced in the dla-4754 advisory.

    - -------------------------------------------------------------------------     Debian LTS Advisory DLA-4754-1                debian-lts@lists.debian.org     https://www.debian.org/lts/security/               Emilio Pozuelo Monfort     August 25, 2026                               https://wiki.debian.org/LTS
    - -------------------------------------------------------------------------

    Package        : thunderbird     Version        : 1:140.14.0esr-1~deb11u1 1:140.14.0esr-1~deb12u1     CVE ID         : CVE-2026-74934 CVE-2026-74935 CVE-2026-74936 CVE-2026-74939                      CVE-2026-74940 CVE-2026-74941 CVE-2026-74942 CVE-2026-74943                      CVE-2026-74944 CVE-2026-74945 CVE-2026-74946 CVE-2026-74948                      CVE-2026-74949 CVE-2026-74953 CVE-2026-74957 CVE-2026-74959                      CVE-2026-74960 CVE-2026-74962 CVE-2026-74963 CVE-2026-74964                      CVE-2026-74965 CVE-2026-74967 CVE-2026-74969 CVE-2026-74971                      CVE-2026-74972 CVE-2026-74973 CVE-2026-74974 CVE-2026-74976                      CVE-2026-74983 CVE-2026-74987 CVE-2026-74990

    Multiple security issues were discovered in Thunderbird, which could     result in the execution of arbitrary code or information disclosure.

    For Debian 11 bullseye, these problems have been fixed in version     1:140.14.0esr-1~deb11u1.

    For Debian 12 bookworm, these problems have been fixed in version     1:140.14.0esr-1~deb12u1.

    We recommend that you upgrade your thunderbird packages.

    For the detailed security status of thunderbird please refer to     its security tracker page at:
    https://security-tracker.debian.org/tracker/thunderbird

    Further information about Debian LTS security advisories, how to apply     these updates to your system and frequently asked questions can be     found at: https://wiki.debian.org/LTS

Tenable has extracted the preceding description block directly from the Debian 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 firefox installed on the remote host is prior to 140.14.0-1. It is, therefore, affected by multiple vulnerabilities as referenced in the ALAS2FIREFOX-2026-064 advisory.

    Expat through 2.8.3 contains a denial of service vulnerability caused by quadratic algorithmic complexity     in the storeAtts() function in xmlparse.c, where processing N specified attributes with non-normalized     values triggers an O(N^2) linear scan of elementType->defaultAtts to determine CDATA status. A remote     unauthenticated attacker can supply a single well-formed XML document of a few megabytes to an application     parsing untrusted XML to cause excessive CPU consumption, resulting in denial of service without requiring     authentication, external entity resolution, or non-default parser options. (CVE-2026-66046)

    libexpat before 2.8.3 has an out-of-bounds read and resultant infinite loop because low surrogates are     treated the same as high surrogates during Unicode processing in the *_toUtf16 functions. (CVE-2026-72522)

    Site isolation issue in the Graphics: CanvasWebGL component. This vulnerability was fixed in Firefox 154,     Firefox ESR 115.39, Firefox ESR 140.14, and Firefox ESR 153.1. (CVE-2026-74934)

    Privilege escalation in the DOM: Networking component. This vulnerability was fixed in Firefox 154,     Firefox ESR 115.39, Firefox ESR 140.14, and Firefox ESR 153.1. (CVE-2026-74935)

    Use-after-free in the JavaScript: WebAssembly component. This vulnerability was fixed in Firefox 154,     Firefox ESR 140.14, and Firefox ESR 153.1. (CVE-2026-74936)

    Mitigation bypass in the JavaScript: GC component. This vulnerability was fixed in Firefox 154, Firefox     ESR 153.1, Thunderbird 154, and Thunderbird 153.1. (CVE-2026-74938)

    Privilege escalation in the DOM: Navigation component. This vulnerability was fixed in Firefox 154,     Firefox ESR 115.39, Firefox ESR 140.14, Firefox ESR 153.1, Thunderbird 154, Thunderbird 140.14, and     Thunderbird 153.1. (CVE-2026-74939)

    Use-after-free in the Graphics: Text component. This vulnerability was fixed in Firefox 154, Firefox ESR     115.39, Firefox ESR 140.14, and Firefox ESR 153.1. (CVE-2026-74940)

    Privilege escalation in the Graphics: CanvasWebGL component. This vulnerability was fixed in Firefox 154,     Firefox ESR 140.14, Firefox ESR 153.1, Thunderbird 154, Thunderbird 140.14, and Thunderbird 153.1.
    (CVE-2026-74941)

    Privilege escalation in the Remote Settings Client component. This vulnerability was fixed in Firefox 154,     Firefox ESR 115.39, Firefox ESR 140.14, and Firefox ESR 153.1. (CVE-2026-74942)

    Use-after-free in the Graphics: ImageLib component. This vulnerability was fixed in Firefox 154, Firefox     ESR 115.39, Firefox ESR 140.14, and Firefox ESR 153.1. (CVE-2026-74943)

    Use-after-free in the DOM: Core & HTML component. This vulnerability was fixed in Firefox 154, Firefox ESR     140.14, and Firefox ESR 153.1. (CVE-2026-74944)

    Information disclosure in the Graphics: Text component. This vulnerability was fixed in Firefox 154,     Firefox ESR 115.39, Firefox ESR 140.14, Firefox ESR 153.1, Thunderbird 154, Thunderbird 140.14, and     Thunderbird 153.1. (CVE-2026-74945)

    Privilege escalation due to incorrect boundary conditions in the Graphics: CanvasWebGL component. This     vulnerability was fixed in Firefox 154, Firefox ESR 115.39, Firefox ESR 140.14, and Firefox ESR 153.1.
    (CVE-2026-74946)

    Information disclosure in the Graphics component. This vulnerability was fixed in Firefox 154, Firefox ESR     115.39, Firefox ESR 140.14, and Firefox ESR 153.1. (CVE-2026-74948)

    Privilege escalation due to use-after-free in the Graphics: Canvas2D component. This vulnerability was     fixed in Firefox 154, Firefox ESR 140.14, and Firefox ESR 153.1. (CVE-2026-74949)

    Privilege escalation in the Downloads API component. This vulnerability was fixed in Firefox 154, Firefox     ESR 153.1, Thunderbird 154, and Thunderbird 153.1. (CVE-2026-74950)

    Privilege escalation in the Networking: Cookies component. This vulnerability was fixed in Firefox 154,     Firefox ESR 140.14, and Firefox ESR 153.1. (CVE-2026-74953)

    Mitigation bypass in the Safe Browsing component. This vulnerability was fixed in Firefox 154, Firefox ESR     140.14, Firefox ESR 153.1, Thunderbird 154, Thunderbird 140.14, and Thunderbird 153.1. (CVE-2026-74957)

    Mitigation bypass in the Storage: Cache API component. This vulnerability was fixed in Firefox 154,     Firefox ESR 140.14, Firefox ESR 153.1, Thunderbird 154, Thunderbird 140.14, and Thunderbird 153.1.
    (CVE-2026-74959)

    Site isolation issue in the WebExtensions component. This vulnerability was fixed in Firefox 154, Firefox     ESR 140.14, Firefox ESR 153.1, Thunderbird 154, Thunderbird 140.14, and Thunderbird 153.1.
    (CVE-2026-74960)

    Site isolation issue in the Networking: Cookies component. This vulnerability was fixed in Firefox 154,     Firefox ESR 140.14, Firefox ESR 153.1, Thunderbird 154, Thunderbird 140.14, and Thunderbird 153.1.
    (CVE-2026-74962)

    Same-origin policy bypass in the Networking: Cookies component. This vulnerability was fixed in Firefox     154, Firefox ESR 140.14, Firefox ESR 153.1, Thunderbird 154, Thunderbird 140.14, and Thunderbird 153.1.
    (CVE-2026-74963)

    Integer overflow in the Graphics component. This vulnerability was fixed in Firefox 154, Firefox ESR     140.14, Firefox ESR 153.1, Thunderbird 154, Thunderbird 140.14, and Thunderbird 153.1. (CVE-2026-74964)

    Privilege escalation in the Shell Integration component. This vulnerability was fixed in Firefox 154,     Firefox ESR 140.14, Firefox ESR 153.1, Thunderbird 154, Thunderbird 140.14, and Thunderbird 153.1.
    (CVE-2026-74965)

    Same-origin policy bypass in the Audio/Video: Playback component. This vulnerability was fixed in Firefox     154, Firefox ESR 140.14, Firefox ESR 153.1, Thunderbird 154, Thunderbird 140.14, and Thunderbird 153.1.
    (CVE-2026-74967)

    Site isolation issue in the Graphics: WebRender component. This vulnerability was fixed in Firefox 154,     Firefox ESR 153.1, Thunderbird 154, and Thunderbird 153.1. (CVE-2026-74968)

    Use-after-free in the Layout: Text and Fonts component. This vulnerability was fixed in Firefox 154,     Firefox ESR 115.39, Firefox ESR 140.14, Firefox ESR 153.1, Thunderbird 154, Thunderbird 140.14, and     Thunderbird 153.1. (CVE-2026-74969)

    Information disclosure in the DOM: UI Events & Focus Handling component. This vulnerability was fixed in     Firefox 154, Firefox ESR 140.14, Firefox ESR 153.1, Thunderbird 154, Thunderbird 140.14, and Thunderbird     153.1. (CVE-2026-74971)

    Information disclosure in the DOM: Push Subscriptions component. This vulnerability was fixed in Firefox     154, Firefox ESR 140.14, Firefox ESR 153.1, Thunderbird 154, Thunderbird 140.14, and Thunderbird 153.1.
    (CVE-2026-74972)

    Race condition, use-after-free in the Graphics component. This vulnerability was fixed in Firefox 154,     Firefox ESR 115.39, Firefox ESR 140.14, Firefox ESR 153.1, Thunderbird 154, Thunderbird 140.14, and     Thunderbird 153.1. (CVE-2026-74973)

    Same-origin policy bypass in the Graphics: ImageLib component. This vulnerability was fixed in Firefox     154, Firefox ESR 115.39, Firefox ESR 140.14, Firefox ESR 153.1, Thunderbird 154, Thunderbird 140.14, and     Thunderbird 153.1. (CVE-2026-74974)

    JIT miscompilation in the JavaScript Engine: JIT component. This vulnerability was fixed in Firefox 154,     Firefox ESR 140.14, Firefox ESR 153.1, Thunderbird 154, Thunderbird 140.14, and Thunderbird 153.1.
    (CVE-2026-74976)

    Mitigation bypass in the Data Loss Prevention component. This vulnerability was fixed in Firefox 154,     Firefox ESR 140.14, Firefox ESR 153.1, Thunderbird 154, Thunderbird 140.14, and Thunderbird 153.1.
    (CVE-2026-74983)

    Internally found bugs present in Thunderbird ESR 140.13, Thunderbird ESR 153.0 and Thunderbird 153. Some     of these bugs showed evidence of memory corruption or another security-relevant defect and we presume that     with enough effort some of these could have been exploited. This vulnerability was fixed in Firefox 154,     Firefox ESR 140.14, Firefox ESR 153.1, Thunderbird 154, Thunderbird 140.14, and Thunderbird 153.1.
    (CVE-2026-74987)

    Internally found bugs present in Thunderbird ESR 153.0 and Thunderbird 153. Some of these bugs showed     evidence of memory corruption or another security-relevant defect and we presume that with enough effort     some of these could have been exploited. This vulnerability was fixed in Firefox 154, Firefox ESR 153.1,     Thunderbird 154, and Thunderbird 153.1. (CVE-2026-74988)

    Internally found bugs present in Thunderbird ESR 140.13, Thunderbird ESR 153.0 and Thunderbird 153. Some     of these bugs showed evidence of memory corruption or another security-relevant defect and we presume that     with enough effort some of these could have been exploited. This vulnerability was fixed in Firefox 154,     Firefox ESR 115.39, Firefox ESR 140.14, Firefox ESR 153.1, Thunderbird 154, Thunderbird 140.14, and     Thunderbird 153.1. (CVE-2026-74990)

    libexpat before 2.8.4 lacks handler call depth tracking with custom encoding callbacks. Thus, a use-after-     free can occur. NOTE: this is similar to CVE-2026-50219, CVE-2026-56131 and CVE-2026-56412.
    (CVE-2026-76957)

Tenable has extracted the preceding description block directly from the tested product 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 remote Redhat Enterprise Linux 8 host has a package installed that is affected by multiple vulnerabilities as referenced in the RHSA-2026:65160 advisory.

    Mozilla Thunderbird is a standalone mail and newsgroup client.

    Security Fix(es):

    * firefox: thunderbird: Site isolation issue in the Graphics: CanvasWebGL component (CVE-2026-74934)

    * firefox: thunderbird: Privilege escalation in the Networking: Cookies component (CVE-2026-74953)

    * firefox: thunderbird: Internally found bugs fixed in Firefox ESR 140.14, Firefox ESR 153.1 and Firefox     154 (CVE-2026-74987)

    * firefox: thunderbird: Information disclosure in the Graphics component (CVE-2026-74948)

    * firefox: thunderbird: Information disclosure in the DOM: UI Events & Focus Handling component     (CVE-2026-74971)

    * firefox: thunderbird: Privilege escalation in the Graphics: CanvasWebGL component (CVE-2026-74941)

    * firefox: Privilege escalation in the Shell Integration component (CVE-2026-74965)

    * firefox: thunderbird: Privilege escalation due to incorrect boundary conditions in the Graphics:
    CanvasWebGL component (CVE-2026-74946)

    * firefox: Race condition, use-after-free in the Graphics component (CVE-2026-74973)

    * firefox: thunderbird: Internally found bugs fixed in Firefox ESR 115.39, Firefox ESR 140.14, Firefox ESR     153.1 and Firefox 154 (CVE-2026-74990)

    * firefox: thunderbird: Use-after-free in the Graphics: Text component (CVE-2026-74940)

    * firefox: thunderbird: Site isolation issue in the WebExtensions component (CVE-2026-74960)

    * firefox: thunderbird: Mitigation bypass in the Storage: Cache API component (CVE-2026-74959)

    * firefox: thunderbird: JIT miscompilation in the JavaScript Engine: JIT component (CVE-2026-74976)

    * firefox: thunderbird: Same-origin policy bypass in the Graphics: ImageLib component (CVE-2026-74974)

    * firefox: thunderbird: Mitigation bypass in the Safe Browsing component (CVE-2026-74957)

    * firefox: thunderbird: Same-origin policy bypass in the Audio/Video: Playback component (CVE-2026-74967)

    * firefox: Privilege escalation in the Remote Settings Client component (CVE-2026-74942)

    * firefox: thunderbird: Privilege escalation in the DOM: Navigation component (CVE-2026-74939)

    * firefox: thunderbird: Information disclosure in the DOM: Push Subscriptions component (CVE-2026-74972)

    * firefox: thunderbird: Information disclosure in the Graphics: Text component (CVE-2026-74945)

    * firefox: thunderbird: Same-origin policy bypass in the Networking: Cookies component (CVE-2026-74963)

    * firefox: Integer overflow in the Graphics component (CVE-2026-74964)

    * firefox: Site isolation issue in the Networking: Cookies component (CVE-2026-74962)

    * firefox: thunderbird: Privilege escalation in the DOM: Networking component (CVE-2026-74935)

    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 remote Redhat Enterprise Linux 7 host has a package installed that is affected by multiple vulnerabilities as referenced in the RHSA-2026:65442 advisory.

    Mozilla Firefox is an open-source web browser, designed for standards compliance, performance, and     portability.

    Security Fix(es):

    * firefox: thunderbird: Mitigation bypass in the Data Loss Prevention component (CVE-2026-74983)

    * firefox: thunderbird: Site isolation issue in the Graphics: CanvasWebGL component (CVE-2026-74934)

    * firefox: thunderbird: Privilege escalation in the Networking: Cookies component (CVE-2026-74953)

    * firefox: thunderbird: Internally found bugs fixed in Firefox ESR 140.14, Firefox ESR 153.1 and Firefox     154 (CVE-2026-74987)

    * firefox: thunderbird: Information disclosure in the Graphics component (CVE-2026-74948)

    * firefox: thunderbird: Use-after-free in the Graphics: ImageLib component (CVE-2026-74943)

    * firefox: thunderbird: Information disclosure in the DOM: UI Events & Focus Handling component     (CVE-2026-74971)

    * firefox: thunderbird: Privilege escalation in the Graphics: CanvasWebGL component (CVE-2026-74941)

    * firefox: Privilege escalation in the Shell Integration component (CVE-2026-74965)

    * firefox: thunderbird: Privilege escalation due to incorrect boundary conditions in the Graphics:
    CanvasWebGL component (CVE-2026-74946)

    * firefox: Race condition, use-after-free in the Graphics component (CVE-2026-74973)

    * firefox: thunderbird: Privilege escalation due to use-after-free in the Graphics: Canvas2D component     (CVE-2026-74949)

    * firefox: thunderbird: Internally found bugs fixed in Firefox ESR 115.39, Firefox ESR 140.14, Firefox ESR     153.1 and Firefox 154 (CVE-2026-74990)

    * firefox: thunderbird: Use-after-free in the JavaScript: WebAssembly component (CVE-2026-74936)

    * firefox: thunderbird: Use-after-free in the Graphics: Text component (CVE-2026-74940)

    * firefox: thunderbird: Site isolation issue in the WebExtensions component (CVE-2026-74960)

    * firefox: thunderbird: Use-after-free in the Layout: Text and Fonts component (CVE-2026-74969)

    * firefox: thunderbird: Mitigation bypass in the Storage: Cache API component (CVE-2026-74959)

    * firefox: thunderbird: JIT miscompilation in the JavaScript Engine: JIT component (CVE-2026-74976)

    * firefox: thunderbird: Same-origin policy bypass in the Graphics: ImageLib component (CVE-2026-74974)

    * firefox: thunderbird: Mitigation bypass in the Safe Browsing component (CVE-2026-74957)

    * firefox: thunderbird: Same-origin policy bypass in the Audio/Video: Playback component (CVE-2026-74967)

    * firefox: Privilege escalation in the Remote Settings Client component (CVE-2026-74942)

    * firefox: thunderbird: Privilege escalation in the DOM: Navigation component (CVE-2026-74939)

    * firefox: thunderbird: Information disclosure in the DOM: Push Subscriptions component (CVE-2026-74972)

    * firefox: thunderbird: Information disclosure in the Graphics: Text component (CVE-2026-74945)

    * firefox: thunderbird: Same-origin policy bypass in the Networking: Cookies component (CVE-2026-74963)

    * firefox: thunderbird: Use-after-free in the DOM: Core & HTML component (CVE-2026-74944)

    * firefox: Integer overflow in the Graphics component (CVE-2026-74964)

    * firefox: Site isolation issue in the Networking: Cookies component (CVE-2026-74962)

    * firefox: thunderbird: Privilege escalation in the DOM: Networking component (CVE-2026-74935)

    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 remote Redhat Enterprise Linux 9 host has packages installed that are affected by multiple vulnerabilities as referenced in the RHSA-2026:65888 advisory.

    Mozilla Firefox is an open-source web browser, designed for standards compliance, performance, and     portability.

    Security Fix(es):

    * firefox: thunderbird: Mitigation bypass in the Data Loss Prevention component (CVE-2026-74983)

    * firefox: thunderbird: Site isolation issue in the Graphics: CanvasWebGL component (CVE-2026-74934)

    * firefox: thunderbird: Privilege escalation in the Networking: Cookies component (CVE-2026-74953)

    * firefox: thunderbird: Internally found bugs fixed in Firefox ESR 140.14, Firefox ESR 153.1 and Firefox     154 (CVE-2026-74987)

    * firefox: thunderbird: Information disclosure in the Graphics component (CVE-2026-74948)

    * firefox: thunderbird: Use-after-free in the Graphics: ImageLib component (CVE-2026-74943)

    * firefox: thunderbird: Information disclosure in the DOM: UI Events & Focus Handling component     (CVE-2026-74971)

    * firefox: thunderbird: Privilege escalation in the Graphics: CanvasWebGL component (CVE-2026-74941)

    * firefox: Privilege escalation in the Shell Integration component (CVE-2026-74965)

    * firefox: thunderbird: Privilege escalation due to incorrect boundary conditions in the Graphics:
    CanvasWebGL component (CVE-2026-74946)

    * firefox: Race condition, use-after-free in the Graphics component (CVE-2026-74973)

    * firefox: thunderbird: Privilege escalation due to use-after-free in the Graphics: Canvas2D component     (CVE-2026-74949)

    * firefox: thunderbird: Internally found bugs fixed in Firefox ESR 115.39, Firefox ESR 140.14, Firefox ESR     153.1 and Firefox 154 (CVE-2026-74990)

    * firefox: thunderbird: Use-after-free in the JavaScript: WebAssembly component (CVE-2026-74936)

    * firefox: thunderbird: Use-after-free in the Graphics: Text component (CVE-2026-74940)

    * firefox: thunderbird: Site isolation issue in the WebExtensions component (CVE-2026-74960)

    * firefox: thunderbird: Use-after-free in the Layout: Text and Fonts component (CVE-2026-74969)

    * firefox: thunderbird: Mitigation bypass in the Storage: Cache API component (CVE-2026-74959)

    * firefox: thunderbird: JIT miscompilation in the JavaScript Engine: JIT component (CVE-2026-74976)

    * firefox: thunderbird: Same-origin policy bypass in the Graphics: ImageLib component (CVE-2026-74974)

    * firefox: thunderbird: Mitigation bypass in the Safe Browsing component (CVE-2026-74957)

    * firefox: thunderbird: Same-origin policy bypass in the Audio/Video: Playback component (CVE-2026-74967)

    * firefox: Privilege escalation in the Remote Settings Client component (CVE-2026-74942)

    * firefox: thunderbird: Privilege escalation in the DOM: Navigation component (CVE-2026-74939)

    * firefox: thunderbird: Information disclosure in the DOM: Push Subscriptions component (CVE-2026-74972)

    * firefox: thunderbird: Information disclosure in the Graphics: Text component (CVE-2026-74945)

    * firefox: thunderbird: Same-origin policy bypass in the Networking: Cookies component (CVE-2026-74963)

    * firefox: thunderbird: Use-after-free in the DOM: Core & HTML component (CVE-2026-74944)

    * firefox: Integer overflow in the Graphics component (CVE-2026-74964)

    * firefox: Site isolation issue in the Networking: Cookies component (CVE-2026-74962)

    * firefox: thunderbird: Privilege escalation in the DOM: Networking component (CVE-2026-74935)

    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 remote RockyLinux 8 host has packages installed that are affected by multiple vulnerabilities as referenced in the RLSA-2026:65160 advisory.

    * firefox: thunderbird: Site isolation issue in the Graphics: CanvasWebGL component (CVE-2026-74934)

    * firefox: thunderbird: Privilege escalation in the Networking: Cookies component (CVE-2026-74953)

    * firefox: thunderbird: Internally found bugs fixed in Firefox ESR 140.14, Firefox ESR 153.1 and Firefox     154 (CVE-2026-74987)

    * firefox: thunderbird: Information disclosure in the Graphics component (CVE-2026-74948)

    * firefox: thunderbird: Information disclosure in the DOM: UI Events & Focus Handling component     (CVE-2026-74971)

    * firefox: thunderbird: Privilege escalation in the Graphics: CanvasWebGL component (CVE-2026-74941)

    * firefox: Privilege escalation in the Shell Integration component (CVE-2026-74965)

    * firefox: thunderbird: Privilege escalation due to incorrect boundary conditions in the Graphics:
    CanvasWebGL component (CVE-2026-74946)

    * firefox: Race condition, use-after-free in the Graphics component (CVE-2026-74973)

    * firefox: thunderbird: Internally found bugs fixed in Firefox ESR 115.39, Firefox ESR 140.14, Firefox ESR     153.1 and Firefox 154 (CVE-2026-74990)

    * firefox: thunderbird: Use-after-free in the Graphics: Text component (CVE-2026-74940)

    * firefox: thunderbird: Site isolation issue in the WebExtensions component (CVE-2026-74960)

    * firefox: thunderbird: Mitigation bypass in the Storage: Cache API component (CVE-2026-74959)

    * firefox: thunderbird: JIT miscompilation in the JavaScript Engine: JIT component (CVE-2026-74976)

    * firefox: thunderbird: Same-origin policy bypass in the Graphics: ImageLib component (CVE-2026-74974)

    * firefox: thunderbird: Mitigation bypass in the Safe Browsing component (CVE-2026-74957)

    * firefox: thunderbird: Same-origin policy bypass in the Audio/Video: Playback component (CVE-2026-74967)

    * firefox: Privilege escalation in the Remote Settings Client component (CVE-2026-74942)

    * firefox: thunderbird: Privilege escalation in the DOM: Navigation component (CVE-2026-74939)

    * firefox: thunderbird: Information disclosure in the DOM: Push Subscriptions component (CVE-2026-74972)

    * firefox: thunderbird: Information disclosure in the Graphics: Text component (CVE-2026-74945)

    * firefox: thunderbird: Same-origin policy bypass in the Networking: Cookies component (CVE-2026-74963)

    * firefox: Integer overflow in the Graphics component (CVE-2026-74964)

    * firefox: Site isolation issue in the Networking: Cookies component (CVE-2026-74962)

    * firefox: thunderbird: Privilege escalation in the DOM: Networking component (CVE-2026-74935)

Tenable has extracted the preceding description block directly from the RockyLinux 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
337887	Mozilla Thunderbird < 140.14	Nessus	MacOS X Local Security Checks	8/19/2026	8/24/2026	critical
339042	Debian dsa-6461 : thunderbird - security update	Nessus	Debian Local Security Checks	8/23/2026	8/23/2026	critical
339104	RHEL 8 : firefox (RHSA-2026:58898)	Nessus	Red Hat Local Security Checks	8/24/2026	8/28/2026	critical
339449	Debian dla-4754 : thunderbird - security update	Nessus	Debian Local Security Checks	8/25/2026	8/25/2026	critical
341890	Amazon Linux 2 : firefox, --advisory ALAS2FIREFOX-2026-064 (ALASFIREFOX-2026-064)	Nessus	Amazon Linux Local Security Checks	8/31/2026	9/3/2026	high
343858	RHEL 8 : thunderbird (RHSA-2026:65160)	Nessus	Red Hat Local Security Checks	9/8/2026	9/8/2026	critical
343882	RHEL 7 : firefox (RHSA-2026:65442)	Nessus	Red Hat Local Security Checks	9/8/2026	9/8/2026	critical
343989	RHEL 9 : firefox (RHSA-2026:65888)	Nessus	Red Hat Local Security Checks	9/9/2026	9/9/2026	critical
344067	RockyLinux 8 : thunderbird (RLSA-2026:65160)	Nessus	Rocky Linux Local Security Checks	9/9/2026	9/9/2026	critical

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