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.
Published: 2026-10-27
Score: 5.7 Medium
EPSS: < 1% Very Low
KEV: No
Impact: n/a
Action: n/a
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Remediation

No vendor fix or workaround currently provided.

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Tracking

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Advisories
Source ID Title
Debian DLA Debian DLA DLA-4877-1 thunderbird security update
History

Thu, 05 Nov 2026 13:45:00 +0000

Type Values Removed Values Added
Weaknesses CWE-73
References
Metrics threat_severity

None

threat_severity

Important


Wed, 04 Nov 2026 19:30:00 +0000

Type Values Removed Values Added
Weaknesses CWE-200
CWE-22

Wed, 04 Nov 2026 17:30:00 +0000

Type Values Removed Values Added
Weaknesses CWE-829
Metrics cvssV3_1

{'score': 5.7, 'vector': 'CVSS:3.1/AV:N/AC:L/PR:L/UI:R/S:U/C:H/I:N/A:N'}

ssvc

{'options': {'Automatable': 'no', 'Exploitation': 'none', 'Technical Impact': 'partial'}, 'version': '2.0.3'}


Tue, 27 Oct 2026 21:15:00 +0000

Type Values Removed Values Added
Weaknesses CWE-200
CWE-22

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

Subscriptions

Mozilla Thunderbird
cve-icon MITRE

Status: PUBLISHED

Assigner: mozilla

Published:

Updated: 2026-11-04T16:45:21.561Z

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

Link: CVE-2026-118178

cve-icon Vulnrichment

Updated: 2026-11-04T16:45:17.566Z

cve-icon NVD

Status : Deferred

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

Modified: 2026-11-04T17:17:34.120

Link: CVE-2026-118178

cve-icon Redhat

Severity : Important

Publid Date: 2026-11-04T00:00:00Z

Links: CVE-2026-118178 - Bugzilla

cve-icon OpenCVE Enrichment

Updated: 2026-11-05T15:15:19Z

Weaknesses