CVE-2026-118174 Details
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.
A vulnerability exists in Mozilla Thunderbird when handling OpenPGP key attachments. The application automatically loads the content of these attachments to facilitate key importing. However, a sender can designate the attachment as external and point it to an arbitrary URL. Thunderbird will then access this URL without user interaction, circumventing remote content blocking. On Windows systems, this could lead to an unauthorized leak of NTLM credentials if the URL directs to an attacker-controlled network share. While the NTLM credential leak is specific to Windows, the remote content blocking bypass affects Thunderbird on all operating systems.
Users can update to Thunderbird version 159 or Thunderbird 153.6 to address this vulnerability.
Metrics
CVSS 4.0 Severity and Vector Strings:
VolerionCVSS 3.x Severity and Vector Strings:
No data available for CVSS Version 2.0 on this CVE.
Volerion
Assessed Oct 27, 2026CISA-ADP
Assessed Nov 4, 2026References to Advisories, Solutions, and Tools
By selecting these links, you will be leaving this site. These are references gathered from the official CVE record and are not endorsed by Volerion.
| URL | Source(s) | Tag(s) |
|---|---|---|
| https://bugzilla.mozilla.org/show_bug.cgi?id=2080910 | [email protected] | Issue TrackingPermission RequiredVendor |
| https://www.mozilla.org/security/advisories/mfsa2026-121/ | [email protected] | AdvisoryBundleRemedyVendor |
| https://www.mozilla.org/security/advisories/mfsa2026-122/ | [email protected] | AdvisoryBundleRemedyVendor |
Weakness Enumeration
| CWE-ID | CWE Name | Source |
|---|---|---|
| CWE-829 | Inclusion of Functionality from Untrusted Control Sphere | CISA-ADP |
Affected Products
| Product | Versions |
|---|---|
| Mozilla Thunderbird | All versions |
CPE
Remediation
| |
Change History
2 change records found show changes
| Date | Action | Recorded By |
|---|---|---|
| Nov 4, 2026 | CVE Modified | CISA-ADP |
| Oct 27, 2026 | New CVE Received | [email protected] |