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No exploitation reportedFix available

CVE-2026-118180

Matrix homeserver could redirect the chat session to a local file or network share

No exploitation reported by the sources we read.

  • Published2026-10-27
  • WeaknessCWE-601

Am I affected?

With a domain, we read the version its public headers and pages expose. A distribution build can carry the fix under an older number.

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.

Timeline

dates in UTC
  1. 2026-10-2718:16CVE publishedCNA

Versions per branch

Products declared by the CNA1 product

As mozilla, the CNA that assigned this CVE, declared them in the CVE record; versions as written.

  • Mozilla Thunderbird

    Not affected ≥ 153.6, ≤ 153.* · ≥ 159

Source: the CNA record (CVE Program), © The MITRE Corporation,CVE Terms of UseCVE recordupdated 2026-10-27

Distribution builds and vendor advisories

Packages from OSV.dev and products from the vendors' CSAF advisories.

version not verifiedVersions not verified: read as OSV.dev and the vendors publish them, not checked against each vendor's release list.

Packages

  • MozillaThunderbirdopenSUSE:Tumbleweedall versions · fixed in 153.6.0-1.1
  • mozjs102Ubuntu:24.04:LTSall versions · no fixed version listedand 1 other package
  • mozjs38Ubuntu:18.04:LTSall versions · no fixed version listedand 1 other package
  • mozjs52Ubuntu:20.04:LTSall versions · no fixed version listedand 1 other package
  • mozjs78Ubuntu:22.04:LTSall versions · no fixed version listedand 3 other packages
  • thunderbirdDebian:14all versions · no fixed version listed
  • thunderbirdDebian:13all versions · fixed in 1:153.6.0esr-1~deb13u1
  • thunderbirdDebian:12all versions · fixed in 1:153.6.0esr-1~deb12u2

Vendor advisories

  • CVE-2026-118180 Red Hat Product Security10 known affected

    thunderbird: Matrix homeserver could redirect the chat session to a local file or network share

    thunderbird as a component of Red Hat Enterprise Linux 10 · thunderbird.src as a component of Red Hat Enterprise Linux 10 · thunderbird as a component of Red Hat Enterprise Linux 6 · +7 more

Full record on NVD

Fix

  1. No fix available, says the vendor Red Hat Product Security CVE-2026-118180 · 6 productsFix deferred
  2. No fix planned, says the vendor Red Hat Product Security CVE-2026-118180 · 4 productsOut of support scope

Detection

Nuclei template
none so far
ProjectDiscovery
Exploit-DB
no entry
Exploit-DB
Metasploit modules
none listed
Metasploit Framework

Sources

Identifiers

Technical details

CVSS v3 Vector
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:N
Published
2026-10-27
Last Modified
2026-11-04
NVD status
Deferred
GitHub Advisory
GHSA-x88m-7whj-m9mh

Frequently asked questions

What is CVE-2026-118180?

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.

Is CVE-2026-118180 actively exploited?

Active exploitation of CVE-2026-118180 has not been confirmed. Its EPSS score was 0.2% on 2026-11-04, the estimated probability of exploitation in the next 30 days.

What is the CVSS score for CVE-2026-118180?

CVE-2026-118180 has a CVSS v3 base score of 7.5 (HIGH severity), with vector string CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:N.

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