# CVE-2026-118180: thunderbird: When logging in to a Matrix account, Thunderbird used the homeserver address provided in the server's login response...

CVE-2026-118180 is fixed in thunderbird on 1 platform, first by DEBIAN-CVE-2026-118180, released October 31, 2026. It is not reported as exploited. Patch Radar priority: High.

- Web page: https://patchblox.com/security/cve/CVE-2026-118180
- Priority: High
- CVSS: 7.5 (high)
- EPSS: 0.0032
- CISA KEV: not listed
- Exploited (vendor report): no
- Publicly disclosed: no
- Published: Oct 27, 2026

## 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.

## Where it's fixed

| Platform | Product | Fixed in | Fix | Released |
|---|---|---|---|---|
| Linux | thunderbird Debian 12.15 (bookworm) | 1:153.6.0esr-1~deb12u2 | [DEBIAN-CVE-2026-118180](https://patchblox.com/security/data/fix/linux/debian-cve-2026-118180.md) | Oct 31, 2026 |
| Linux | thunderbird Debian 13.5 (trixie) | 1:153.6.0esr-1~deb13u1 | [DEBIAN-CVE-2026-118180](https://patchblox.com/security/data/fix/linux/debian-cve-2026-118180.md) | Oct 31, 2026 |

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Data as of 2026-11-10T01:44:33Z UTC. Source: Patchblox Patch Radar (https://patchblox.com/security/patch-radar). Patchblox finds out-of-date software on Windows, macOS and Linux and updates it through release rings: https://patchblox.com/demo

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