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.
Advisories

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Fixes

Solution

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Workaround

No workaround given by the vendor.

History

Tue, 27 Oct 2026 20:15:00 +0000

Type Values Removed Values Added
First Time appeared Mozilla
Mozilla thunderbird
Vendors & Products Mozilla
Mozilla thunderbird

Tue, 27 Oct 2026 18:30:00 +0000

Type Values Removed Values Added
Description 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.
Title RSS feed could redirect its subscription to a local file or network share
References

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cve-icon MITRE

Status: PUBLISHED

Assigner: mozilla

Published:

Updated: 2026-10-27T18:27:51.092Z

Reserved: 2026-10-27T18:16:31.563Z

Link: CVE-2026-118178

cve-icon Vulnrichment

No data.

cve-icon NVD

Status : Received

Published: 2026-10-27T19:17:29.480

Modified: 2026-10-27T19:17:29.480

Link: CVE-2026-118178

cve-icon Redhat

No data.

cve-icon OpenCVE Enrichment

Updated: 2026-10-27T20:00:11Z

Weaknesses

No weakness.