When Thunderbird asked for a security device password (for example a smartcard PIN or the Primary Password) while decrypting an S/MIME message, the message load could finish or be cancelled while the prompt was open. This freed the message decoder while it was still in use, causing a use-after-free and a potentially exploitable crash. This vulnerability was fixed in Thunderbird 158.0.1 and Thunderbird 153.6.

The remote Oracle Linux 9 host has a package installed that is affected by multiple vulnerabilities as referenced in the ELSA-2026-96081 advisory.

    [153.6.0-1.0.1]
    - Fix prefs for new nss [Orabug: 37079813]
    - Add Oracle prefs

    [153.6.0]
    - Add OpenELA debranding

    [153.6.0-1]
    - Update to 153.6.0 ESR

Tenable has extracted the preceding description block directly from the Oracle 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 Oracle Linux 10 host has a package installed that is affected by multiple vulnerabilities as referenced in the ELSA-2026-96079 advisory.

    [153.6.0-1.0.1]
    - Add Oracle prefs

    [153.6.0-1]
    - Update to 153.6.0 ESR

Tenable has extracted the preceding description block directly from the Oracle 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 AlmaLinux 9.2 host has a package installed that is affected by multiple vulnerabilities as referenced in the TuxCare ALMALINUX9.2:CLSA-2026:1793952112 advisory.

  - Sandbox escape due to incorrect boundary conditions in the Graphics: CanvasWebGL component. This     vulnerability was fixed in Firefox 159, Firefox ESR 153.6, Thunderbird 159, and Thunderbird 153.6.
    (CVE-2026-117988)

  - Use-after-free in the Layout: Text and Fonts component. This vulnerability was fixed in Firefox 159,     Firefox ESR 153.6, Thunderbird 159, and Thunderbird 153.6. (CVE-2026-117877, CVE-2026-117902)

  - Use-after-free in the DOM: Core & HTML component. This vulnerability was fixed in Firefox 159, Firefox ESR     115.44, Firefox ESR 153.6, Thunderbird 159, and Thunderbird 153.6. (CVE-2026-117881, CVE-2026-117887,     CVE-2026-117919, CVE-2026-117925, CVE-2026-117936, CVE-2026-117949, CVE-2026-117951)

  - Same-origin policy bypass in the Address Bar component. This vulnerability was fixed in Firefox 159,     Firefox ESR 153.6, Thunderbird 159, and Thunderbird 153.6. (CVE-2026-117965)

  - Use-after-free in the Layout component. This vulnerability was fixed in Firefox 159, Firefox ESR 115.44,     Firefox ESR 153.6, Thunderbird 159, and Thunderbird 153.6. (CVE-2026-117882)

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 153.6. 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 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 Thunderbird installed on the remote Windows host is prior to 158.0.1. It is, therefore, affected by multiple vulnerabilities as referenced in the mfsa2026-114 advisory.

  - Mozilla blocked compromised intermediate eMudhra certificates via OneCRL on the 17th of October which was     distributed to clients via RemoteSettings the same day. This update contains the updated OneCRL block     list, ensuring clients will block the compromised certificates even if RemoteSettings is disabled by     policy or otherwise unavailable in the user's network environment. (CVE-2026-113470)

  - When setting up an account, Thunderbird's Exchange AutoDiscover lookup also queried the domain's     AutoDiscover service over plain HTTP. Due to a bug, that unencrypted request included the credentials the     user had entered, allowing a network attacker to obtain the user's password. (CVE-2026-113866)

  - Thunderbird did not escape attribute values when serializing outgoing XMPP stanzas. Because values from     incoming requests were echoed back in automatic replies, a remote XMPP user could send a crafted request     that caused Thunderbird to inject arbitrary stanzas into the user's connection, which the server would     then process as if sent by the user. This could be used to send messages or change contact and     subscription settings on behalf of the user, without any interaction. This bug only affects Thunderbird's     chat feature with XMPP accounts. (CVE-2026-113867)

  - When authenticating to a POP3 or SMTP server using NTLM, Thunderbird did not check whether the server's     challenge was valid base64. A malicious server could send a challenge that caused Thunderbird to include     uninitialized heap memory in its NTLM response, disclosing that memory to the server. A challenge     consisting only of base64 padding also caused an out-of-bounds read, crashing Thunderbird. This affected     accounts configured to use NTLM or GSSAPI authentication. The uninitialized memory disclosure only     affected NTLM. (CVE-2026-113868)

  - When Thunderbird asked for a security device password (for example a smartcard PIN or the Primary     Password) while decrypting an S/MIME message, the message load could finish or be cancelled while the     prompt was open. This freed the message decoder while it was still in use, causing a use-after-free and a     potentially exploitable crash. (CVE-2026-113869)

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 158.0.1. It is, therefore, affected by multiple vulnerabilities as referenced in the mfsa2026-114 advisory.

  - Mozilla blocked compromised intermediate eMudhra certificates via OneCRL on the 17th of October which was     distributed to clients via RemoteSettings the same day. This update contains the updated OneCRL block     list, ensuring clients will block the compromised certificates even if RemoteSettings is disabled by     policy or otherwise unavailable in the user's network environment. (CVE-2026-113470)

  - When setting up an account, Thunderbird's Exchange AutoDiscover lookup also queried the domain's     AutoDiscover service over plain HTTP. Due to a bug, that unencrypted request included the credentials the     user had entered, allowing a network attacker to obtain the user's password. (CVE-2026-113866)

  - Thunderbird did not escape attribute values when serializing outgoing XMPP stanzas. Because values from     incoming requests were echoed back in automatic replies, a remote XMPP user could send a crafted request     that caused Thunderbird to inject arbitrary stanzas into the user's connection, which the server would     then process as if sent by the user. This could be used to send messages or change contact and     subscription settings on behalf of the user, without any interaction. This bug only affects Thunderbird's     chat feature with XMPP accounts. (CVE-2026-113867)

  - When authenticating to a POP3 or SMTP server using NTLM, Thunderbird did not check whether the server's     challenge was valid base64. A malicious server could send a challenge that caused Thunderbird to include     uninitialized heap memory in its NTLM response, disclosing that memory to the server. A challenge     consisting only of base64 padding also caused an out-of-bounds read, crashing Thunderbird. This affected     accounts configured to use NTLM or GSSAPI authentication. The uninitialized memory disclosure only     affected NTLM. (CVE-2026-113868)

  - When Thunderbird asked for a security device password (for example a smartcard PIN or the Primary     Password) while decrypting an S/MIME message, the message load could finish or be cancelled while the     prompt was open. This freed the message decoder while it was still in use, causing a use-after-free and a     potentially exploitable crash. (CVE-2026-113869)

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.

  - When Thunderbird asked for a security device password (for example a smartcard PIN or the Primary     Password) while decrypting an S/MIME message, the message load could finish or be cancelled while the     prompt was open. This freed the message decoder while it was still in use, causing a use-after-free and a     potentially exploitable crash. This vulnerability was fixed in Thunderbird 158.0.1 and Thunderbird 153.6.
    (CVE-2026-113869)

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

ID	Name	Product	Family	Type	Severity
377972	Oracle Linux 9 : thunderbird (ELSA-2026-96081)	Nessus	Oracle Linux Local Security Checks	Local	high
377734	Oracle Linux 10 : thunderbird (ELSA-2026-96079)	Nessus	Oracle Linux Local Security Checks	Local	high
377000	AlmaLinux 9.2 [TuxCare] Security Update: thunderbird Multiple Vulnerabilities (ALMALINUX9.2:CLSA-2026:1793952112)	Nessus	Alma Linux Local Security Checks	Local	critical
372632	Mozilla Thunderbird < 153.6	Nessus	Windows	Local	critical
372624	Mozilla Thunderbird < 153.6	Nessus	MacOS X Local Security Checks	Local	critical
369077	Mozilla Thunderbird < 158.0.1	Nessus	Windows	Local	critical
369076	Mozilla Thunderbird < 158.0.1	Nessus	MacOS X Local Security Checks	Local	critical
369012	Linux Distros Unpatched Vulnerability : CVE-2026-113869	Nessus	Misc.	Local	medium

Detections

Analytics

CVE-2026-113869

medium

Tenable Plugins

high

high

critical

critical

critical

critical

critical

medium