Vulnerability Description
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. This vulnerability was fixed in Thunderbird 159 and Thunderbird 153.6.
References
- https://bugzilla.mozilla.org/show_bug.cgi?id=2080910
- https://www.mozilla.org/security/advisories/mfsa2026-121/
- https://www.mozilla.org/security/advisories/mfsa2026-122/
FAQ
What is CVE-2026-118174?
CVE-2026-118174 is a documented vulnerability. 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 extern...
How severe is CVE-2026-118174?
CVSS scoring is not yet available for CVE-2026-118174. Check NVD for updates.
Is there a patch for CVE-2026-118174?
Check the references section above for vendor advisories and patch information. Review vendor security bulletins for remediation guidance.