Vulnerability · Published Oct 27, 2026 · Assigned by mozilla
CVE-2026-118174Displaying a message could load an attacker-chosen URL through an OpenPGP key attachment
Medium 6.5
In plain English
A medium-severity security flaw in Thunderbird from Mozilla. There are no confirmed reports of exploitation so far. The chance it is exploited in the next 30 days is estimated at 0.4% (higher than 31% of all known vulnerabilities). Fixed versions are available - upgrade the affected package.
Official 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.
Affected packages & fixed versions
| Ecosystem | Package | Fixed in | Advisory |
|---|---|---|---|
| Debian:12 | thunderbird | 1:153.6.0esr-1~deb12u2 | DEBIAN-CVE-2026-118174 |
| Debian:13 | thunderbird | 1:153.6.0esr-1~deb13u1 | DEBIAN-CVE-2026-118174 |
| Debian:14 | thunderbird | no fix listed | DEBIAN-CVE-2026-118174 |
| Ubuntu:22.04:LTS | mozjs102 | no fix listed | UBUNTU-CVE-2026-118174 |
| Ubuntu:24.04:LTS | mozjs102 | no fix listed | UBUNTU-CVE-2026-118174 |
| Ubuntu:24.04:LTS | mozjs115 | no fix listed | UBUNTU-CVE-2026-118174 |
| Ubuntu:22.04:LTS | mozjs78 | no fix listed | UBUNTU-CVE-2026-118174 |
| Ubuntu:22.04:LTS | mozjs91 | no fix listed | UBUNTU-CVE-2026-118174 |
| Ubuntu:22.04:LTS | thunderbird | no fix listed | UBUNTU-CVE-2026-118174 |
Affected products (as reported)
| Vendor | Product | Versions |
|---|---|---|
| Mozilla | Thunderbird | see references |
Weakness: CWE-829 · Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:N/A:N