CVE-2026-118180 Matrix homeserver could redirect the chat session to a local file or network share
- Exploited in the wild
- Not known
- Fix
- None listed
What is CVE-2026-118180?
CVE-2026-118180 is a vulnerability in Mozilla Thunderbird, published on 27 Oct 2026.
Official 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.
Which versions are affected by CVE-2026-118180?
How do I fix CVE-2026-118180?
No fix has been published for CVE-2026-118180 yet. Limit exposure of the affected software until one is available.
Is CVE-2026-118180 being exploited?
There is no known exploitation of CVE-2026-118180 in the wild and no public exploit code.
Sources
Also known as DEBIAN-CVE-2026-118180, GHSA-x88m-7whj-m9mh, UBUNTU-CVE-2026-118180.