Description
When a message containing an OpenPGP key attachment was displayed, Thunderbird automatically loaded the attachment's content to offer importing the key. A sender could mark the attachment as an external attachment pointing to an arbitrary URL, which Thunderbird then loaded without any user interaction, bypassing remote content blocking. On Windows, a URL pointing to an attacker-controlled network share could leak the user's NTLM credentials.
The NTLM credential leak only affects Thunderbird on Windows. On other operating systems, the issue allowed a remote request that bypassed remote content blocking. This vulnerability was fixed in Thunderbird 159 and Thunderbird 153.6.
Published: 2026-10-27
Score: n/a
EPSS: n/a
KEV: No
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Remediation

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History

Tue, 27 Oct 2026 19:45:00 +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 When a message containing an OpenPGP key attachment was displayed, Thunderbird automatically loaded the attachment's content to offer importing the key. A sender could mark the attachment as an external attachment pointing to an arbitrary URL, which Thunderbird then loaded without any user interaction, bypassing remote content blocking. On Windows, a URL pointing to an attacker-controlled network share could leak the user's NTLM credentials. The NTLM credential leak only affects Thunderbird on Windows. On other operating systems, the issue allowed a remote request that bypassed remote content blocking. This vulnerability was fixed in Thunderbird 159 and Thunderbird 153.6.
Title Displaying a message could load an attacker-chosen URL through an OpenPGP key attachment
References

Subscriptions

Mozilla Thunderbird
cve-icon MITRE

Status: PUBLISHED

Assigner: mozilla

Published:

Updated: 2026-10-27T18:27:46.521Z

Reserved: 2026-10-27T18:16:28.266Z

Link: CVE-2026-118174

cve-icon Vulnrichment

No data.

cve-icon NVD

Status : Received

Published: 2026-10-27T19:17:29.037

Modified: 2026-10-27T19:17:29.037

Link: CVE-2026-118174

cve-icon Redhat

No data.

cve-icon OpenCVE Enrichment

Updated: 2026-10-27T19:30:09Z

Weaknesses

No weakness.