CVE-2026-118178
RSS feed could redirect its subscription to a local file or network share
A remote RSS feed could use the itunes:new-feed-url or newLocation element to permanently change its stored subscription URL to a file: URL. Thunderbird then read that location on every feed update. This allowed a malicious feed, or an attacker able to modify a feed delivered over HTTP, to make Thunderbird read local files and, on Windows, connect 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 affected by the local file read only. This vulnerability was fixed in Thunderbird 159 and Thunderbird 153.6.
Fixes and workarounds
No remediation reported in collected sources.
Missing remediation information is not evidence that no patch exists.
Affected products and versions
| Product | Versions | Authority |
|---|---|---|
| Thunderbird Mozilla |
≥ 153.6; ≤ 153.* (unaffected, rpm) ≥ 159; ≤ * (unaffected, rpm) |
CNA: mozilla |
Version ranges are source assertions. Check the vendor advisory and your installed configuration before determining exposure.
CVSS assessments
| Version / score | Vector | Authority |
|---|---|---|
| 3.1 / 5.7 medium |
CVSS:3.1/AV:N/AC:L/PR:L/UI:R/S:U/C:H/I:N/A:N | ADP: CISA-ADP |
| 3.1 / 5.7 medium |
CVSS:3.1/AV:N/AC:L/PR:L/UI:R/S:U/C:H/I:N/A:N | NVD: 134c704f-9b21-4f2e-91b3-4a467353bcc0 |
Exploit evidence
No exploit evidence in collected sources. This is not proof of no exploitation.
References
- https://bugzilla.mozilla.org/show_bug.cgi?id=2075772CNA: mozilla
- https://www.mozilla.org/security/advisories/mfsa2026-121/CNA: mozilla
- https://www.mozilla.org/security/advisories/mfsa2026-122/CNA: mozilla
- https://bugzilla.mozilla.org/show_bug.cgi?id=2075772[email protected]
- https://www.mozilla.org/security/advisories/mfsa2026-121/[email protected]
- https://www.mozilla.org/security/advisories/mfsa2026-122/[email protected]
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