Vulnerability Description
When logging in to a Matrix account, Thunderbird used the homeserver address provided in the server's login response without validating it. A malicious or compromised homeserver could provide a file: URL, causing Thunderbird to send all further Matrix requests of that session to local files or, on Windows, to an attacker-controlled network share, which could leak the user's NTLM credentials. The NTLM credential leak only affects Thunderbird on Windows. Other operating systems are unaffected. This vulnerability was fixed in Thunderbird 159 and Thunderbird 153.6.
References
- https://bugzilla.mozilla.org/show_bug.cgi?id=2080939
- https://www.mozilla.org/security/advisories/mfsa2026-121/
- https://www.mozilla.org/security/advisories/mfsa2026-122/
FAQ
What is CVE-2026-118180?
CVE-2026-118180 is a documented vulnerability. When logging in to a Matrix account, Thunderbird used the homeserver address provided in the server's login response without validating it. A malicious or compromised homeserver could provide a file: ...
How severe is CVE-2026-118180?
CVSS scoring is not yet available for CVE-2026-118180. Check NVD for updates.
Is there a patch for CVE-2026-118180?
Check the references section above for vendor advisories and patch information. Review vendor security bulletins for remediation guidance.