The version of Thunderbird installed on the remote Windows host is prior to 159.0. It is, therefore, affected by multiple vulnerabilities as referenced in the mfsa2026-121 advisory.

  - Privilege escalation in the DOM: Navigation component. This vulnerability was fixed in Firefox 159.
    (CVE-2026-118008)

  - When a message containing an OpenPGP key attachment was displayed, Thunderbird automatically loaded the     attachment's content to offer importing the key. A sender could mark the attachment as an external     attachment pointing to an arbitrary URL, which Thunderbird then loaded without any user interaction,     bypassing remote content blocking. On Windows, a URL pointing to an attacker-controlled network share     could leak the user's NTLM credentials.  The NTLM credential leak only affects Thunderbird on Windows. On     other operating systems, the issue allowed a remote request that bypassed remote content blocking.
    (CVE-2026-118174)

  - When replying to, forwarding, or editing a crafted email message as new, Thunderbird could embed parts of     a different message stored in the same folder into the message being composed, without showing a blocked     content warning. If the user sent the message, the content of the other message was disclosed to the     recipients. (CVE-2026-118175)

  - Thunderbird's check that prevents mailbox: URLs from accessing files on remote Windows network shares     could be bypassed using extended-length UNC paths. Displaying a specially crafted email could cause     Thunderbird to connect to an SMB server chosen by the attacker, disclosing the user's Windows account name     and NTLM authentication data, which could be used for offline password cracking or relay attacks.  This     bug only affects Thunderbird on Windows. Other operating systems are unaffected. (CVE-2026-118176)

  - When looking for calendars in a directory on a server, during account setup or when adding a new network     calendar, Thunderbird accepted calendar locations pointing to other servers, local files or network     shares. A malicious server, or a network attacker when the lookup used plain HTTP, could make Thunderbird     subscribe to such a location. On Windows this could leak the user's NTLM credentials to an attacker-     controlled host on every calendar refresh, and changes to the calendar could be written to the attacker's     share or overwrite a local file. (CVE-2026-118177)

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 159.0. It is, therefore, affected by multiple vulnerabilities as referenced in the mfsa2026-118 advisory.

  - Privilege escalation in the DOM: Navigation component. This vulnerability was fixed in Firefox 159.
    (CVE-2026-118008)

  - Same-origin policy bypass in the DOM: Navigation component. This vulnerability was fixed in Firefox 159,     Firefox ESR 153.6, Thunderbird 159, and Thunderbird 153.6. (CVE-2026-117860)

  - Sandbox escape in the DOM: Navigation component. This vulnerability was fixed in Firefox 159, Firefox ESR     153.6, Thunderbird 159, and Thunderbird 153.6. (CVE-2026-117861)

  - Privilege escalation due to incorrect boundary conditions in the Networking component. This vulnerability     was fixed in Firefox 159, Firefox ESR 115.44, Firefox ESR 153.6, Thunderbird 159, and Thunderbird 153.6.
    (CVE-2026-117862)

  - Information disclosure due to uninitialized memory in the Audio/Video component. This vulnerability was     fixed in Firefox 159, Firefox ESR 115.44, Firefox ESR 153.6, Thunderbird 159, and Thunderbird 153.6.
    (CVE-2026-117863)

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 12 host has packages installed that are affected by multiple vulnerabilities as referenced in the dla-4877 advisory.

    - -------------------------------------------------------------------------     Debian LTS Advisory DLA-4877-1                debian-lts@lists.debian.org     https://www.debian.org/lts/security/               Emilio Pozuelo Monfort     November 02, 2026                             https://wiki.debian.org/LTS
    - -------------------------------------------------------------------------

    Package        : thunderbird     Version        : 1:153.6.0esr-1~deb12u2     CVE ID         : CVE-2026-117860 CVE-2026-117861 CVE-2026-117862 CVE-2026-117863                      CVE-2026-117864 CVE-2026-117865 CVE-2026-117866 CVE-2026-117867                      CVE-2026-117868 CVE-2026-117869 CVE-2026-117870 CVE-2026-117871                      CVE-2026-117872 CVE-2026-117873 CVE-2026-117874 CVE-2026-117875                      CVE-2026-117876 CVE-2026-117877 CVE-2026-117878 CVE-2026-117879                      CVE-2026-117880 CVE-2026-117881 CVE-2026-117882 CVE-2026-117883                      CVE-2026-117884 CVE-2026-117885 CVE-2026-117886 CVE-2026-117887                      CVE-2026-117888 CVE-2026-117889 CVE-2026-117890 CVE-2026-117891                      CVE-2026-117892 CVE-2026-117893 CVE-2026-117894 CVE-2026-117895                      CVE-2026-117896 CVE-2026-117897 CVE-2026-117898 CVE-2026-117899                      CVE-2026-117900 CVE-2026-117901 CVE-2026-117902 CVE-2026-117903                      CVE-2026-117904 CVE-2026-117905 CVE-2026-117906 CVE-2026-117907                      CVE-2026-117908 CVE-2026-117909 CVE-2026-117910 CVE-2026-117911                      CVE-2026-117912 CVE-2026-117913 CVE-2026-117914 CVE-2026-117915                      CVE-2026-117916 CVE-2026-117917 CVE-2026-117918 CVE-2026-117919                      CVE-2026-117920 CVE-2026-117921 CVE-2026-117922 CVE-2026-117923                      CVE-2026-117924 CVE-2026-117925 CVE-2026-117926 CVE-2026-117927                      CVE-2026-117928 CVE-2026-117929 CVE-2026-117930 CVE-2026-117931                      CVE-2026-117932 CVE-2026-117933 CVE-2026-117934 CVE-2026-117935                      CVE-2026-117936 CVE-2026-117937 CVE-2026-117938 CVE-2026-117939                      CVE-2026-117940 CVE-2026-117941 CVE-2026-117942 CVE-2026-117943                      CVE-2026-117944 CVE-2026-117945 CVE-2026-117946 CVE-2026-117947                      CVE-2026-117948 CVE-2026-117949 CVE-2026-117950 CVE-2026-117951                      CVE-2026-117952 CVE-2026-117953 CVE-2026-117954 CVE-2026-117955                      CVE-2026-117956 CVE-2026-117957 CVE-2026-117958 CVE-2026-117959                      CVE-2026-117960 CVE-2026-117961 CVE-2026-117962 CVE-2026-117963                      CVE-2026-117964 CVE-2026-117965 CVE-2026-117966 CVE-2026-117967                      CVE-2026-117968 CVE-2026-117969 CVE-2026-117970 CVE-2026-117971                      CVE-2026-117972 CVE-2026-117973 CVE-2026-117974 CVE-2026-117975                      CVE-2026-117976 CVE-2026-117977 CVE-2026-117978 CVE-2026-117979                      CVE-2026-117980 CVE-2026-117981 CVE-2026-117982 CVE-2026-117983                      CVE-2026-117984 CVE-2026-117985 CVE-2026-117986 CVE-2026-117987                      CVE-2026-117988 CVE-2026-117989 CVE-2026-117990 CVE-2026-117991                      CVE-2026-117992 CVE-2026-117993 CVE-2026-117994 CVE-2026-117995                      CVE-2026-117996 CVE-2026-117997 CVE-2026-117998 CVE-2026-117999                      CVE-2026-118000 CVE-2026-118002 CVE-2026-118003 CVE-2026-118004                      CVE-2026-118174 CVE-2026-118175 CVE-2026-118176 CVE-2026-118177                      CVE-2026-118178 CVE-2026-118179 CVE-2026-118180

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

    For Debian 12 bookworm, these problems have been fixed in version     1:153.6.0esr-1~deb12u2.

    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 Thunderbird installed on the remote macOS or Mac OS X host is prior to 153.6. It is, therefore, affected by multiple vulnerabilities as referenced in the mfsa2026-122 advisory.

  - Privilege escalation in the DLL Services component. This vulnerability was fixed in Firefox ESR 153.4,     Thunderbird 157, Thunderbird 140.17, Thunderbird 153.4, Firefox 159, Firefox ESR 153.6, Thunderbird 159,     Thunderbird 153.6, Firefox 157, and Firefox ESR 140.17. (CVE-2026-100801)

  - When a message containing an OpenPGP key attachment was displayed, Thunderbird automatically loaded the     attachment's content to offer importing the key. A sender could mark the attachment as an external     attachment pointing to an arbitrary URL, which Thunderbird then loaded without any user interaction,     bypassing remote content blocking. On Windows, a URL pointing to an attacker-controlled network share     could leak the user's NTLM credentials.  The NTLM credential leak only affects Thunderbird on Windows. On     other operating systems, the issue allowed a remote request that bypassed remote content blocking.
    (CVE-2026-118174)

  - When replying to, forwarding, or editing a crafted email message as new, Thunderbird could embed parts of     a different message stored in the same folder into the message being composed, without showing a blocked     content warning. If the user sent the message, the content of the other message was disclosed to the     recipients. (CVE-2026-118175)

  - Thunderbird's check that prevents mailbox: URLs from accessing files on remote Windows network shares     could be bypassed using extended-length UNC paths. Displaying a specially crafted email could cause     Thunderbird to connect to an SMB server chosen by the attacker, disclosing the user's Windows account name     and NTLM authentication data, which could be used for offline password cracking or relay attacks.  This     bug only affects Thunderbird on Windows. Other operating systems are unaffected. (CVE-2026-118176)

  - When looking for calendars in a directory on a server, during account setup or when adding a new network     calendar, Thunderbird accepted calendar locations pointing to other servers, local files or network     shares. A malicious server, or a network attacker when the lookup used plain HTTP, could make Thunderbird     subscribe to such a location. On Windows this could leak the user's NTLM credentials to an attacker-     controlled host on every calendar refresh, and changes to the calendar could be written to the attacker's     share or overwrite a local file. (CVE-2026-118177)

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 153.6. It is, therefore, affected by multiple vulnerabilities as referenced in the mfsa2026-120 advisory.

  - Privilege escalation in the DLL Services component. This vulnerability was fixed in Firefox ESR 153.4,     Thunderbird 157, Thunderbird 140.17, Thunderbird 153.4, Firefox 159, Firefox ESR 153.6, Thunderbird 159,     Thunderbird 153.6, Firefox 157, and Firefox ESR 140.17. (CVE-2026-100801)

  - Same-origin policy bypass in the DOM: Navigation component. This vulnerability was fixed in Firefox 159,     Firefox ESR 153.6, Thunderbird 159, and Thunderbird 153.6. (CVE-2026-117860)

  - Sandbox escape in the DOM: Navigation component. This vulnerability was fixed in Firefox 159, Firefox ESR     153.6, Thunderbird 159, and Thunderbird 153.6. (CVE-2026-117861)

  - Privilege escalation due to incorrect boundary conditions in the Networking component. This vulnerability     was fixed in Firefox 159, Firefox ESR 115.44, Firefox ESR 153.6, Thunderbird 159, and Thunderbird 153.6.
    (CVE-2026-117862)

  - Information disclosure due to uninitialized memory in the Audio/Video component. This vulnerability was     fixed in Firefox 159, Firefox ESR 115.44, Firefox ESR 153.6, Thunderbird 159, and Thunderbird 153.6.
    (CVE-2026-117863)

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
372628	Mozilla Thunderbird < 159.0	Nessus	Windows	10/27/2026	11/6/2026	critical
372631	Mozilla Firefox < 159.0	Nessus	MacOS X Local Security Checks	10/27/2026	11/6/2026	critical
374914	Debian dla-4877 : thunderbird - security update	Nessus	Debian Local Security Checks	11/2/2026	11/6/2026	critical
372624	Mozilla Thunderbird < 153.6	Nessus	MacOS X Local Security Checks	10/27/2026	11/6/2026	critical
372629	Mozilla Firefox ESR < 153.6	Nessus	MacOS X Local Security Checks	10/27/2026	11/6/2026	critical

Detections

Analytics

Plugins Search

critical

critical

critical

critical

critical