CVE-2026-126134

UNKNOWN 0.0

Feed subscriptions could leak NTLM credentials on Windows

CVSS Score

0.0

EPSS Score

0.0%

EPSS Percentile

0th

Thunderbird allowed feed subscriptions to file: URLs that point to a network share. If a user was tricked into subscribing to such a URL, Thunderbird connected to the attacker's server when fetching the feed. Windows then sent the user's NTLM credentials to that server. This bug only affects Thunderbird on Windows. Other operating systems are unaffected. This vulnerability was fixed in Thunderbird 160 and Thunderbird 153.7.

Vendor	mozilla
Product	thunderbird
Ecosystems	Browser JavaScript
Industries	Technology
Published	Nov 10, 2026
Last Updated	Nov 10, 2026

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Affected Versions

Mozilla / Thunderbird

All versions affected

References

NVD ↗ CVE.org ↗ EPSS Data ↗

bugzilla.mozilla.org: https://bugzilla.mozilla.org/show_bug.cgi?id=2083584 mozilla.org: https://www.mozilla.org/security/advisories/mfsa2026-128/ mozilla.org: https://www.mozilla.org/security/advisories/mfsa2026-129/

Credits

Magnus Melin