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Not yet scoredPublished Oct 27, 2026

CVE-2026-118180Matrix homeserver could redirect the chat session to a local file or network share

Updated under an hour ago ()

Does this affect you?

It affects Mozilla Thunderbird. Add what you run to find out whether that includes you.

No exploitation reported and no EPSS estimate yet.

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.

CVSS
Not yet scored
Weakness (CWE)
Not given
Known exploited
Not in CISA's KEV catalog
EPSS (exploitation in the next 30 days)
Not loaded for this CVE
Assigned by
mozilla
NVD analysis
Deferred
Record last updated
Oct 27, 2026
First seen by InfoSec Signals
Oct 27, 2026

Affected products

Affected products
Mozilla Thunderbird
mozilla:thunderbird (from the name)
153.6 builds before 153.* not affected; from 159 not affected
CNA record

References

References

The CVE record is authoritative. Products marked “from the name” were identified from the CNA's free-text names, not a CPE, and are matched less certainly. This product uses the NVD API but is not endorsed or certified by the NVD.

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