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.
Fix
Nothing published yet: no patch, vendor advisory or mitigation reference on NVD, no vendor advisory in the News for this CVE, not in CISA's KEV, no fixed package version. BaselineWatch does not guess at one.
Change history 4
- StatusPublished → DeferredNVD modified 2026-10-28 14:42
- StatusReceived → PublishedNVD modified 2026-10-27 18:27
- StatusPublished → ReceivedNVD modified 2026-10-27 19:17
- First seenunscored · mozillaNVD modified 2026-10-27 18:27
Affected (CPE criteria) 0
NVD has not attached CPE configurations yet.