CVE-2026-41431
HIGH EPSS 9.9%
Published May 11, 20261mo ago · Modified Jun 17, 20262w ago
8.0 CVSS 3.1
Published May 11, 2026 1mo ago
Last Modified Jun 17, 2026 2w ago
Description
Zen is a firefox-based browser. Prior to 1.19.9b, Zen Browser ships a Mozilla Application Resource (MAR) updater (org.mozilla.updater) that has had all MAR signature verification stripped from the Firefox codebase it was forked from. The MAR files served to users contain zero cryptographic signatures, and the updater binary contains zero cryptographic verification code. This eliminates the defense-in-depth that MAR signing provides. If the update server or GitHub release pipeline is compromised, arbitrary unsigned code can be delivered to all Zen users via the auto-update mechanism. This vulnerability is fixed in 1.19.9b.
CVSS Details
Base Score
Exploitability
Impact
Vector string
CVSS:3.1/AV:N/AC:H/PR:H/UI:N/S:C/C:H/I:H/A:H Attack Vector Network
Attack Complexity High
Privileges Required High
User Interaction None
Scope Changed
Confidentiality High
Integrity High
Availability High
Threat Intelligence
EPSS Exploit Probability
9.9% percentile
Exploit & Patch Status
No Known Exploit
No Patch Available
Weaknesses 1
CWE-347
References 2
- github.com https://github.com/zen-browser/desktop/commit/270db6d6713d2c6c14d9df0b4bc7662843d3d54e
- github.com https://github.com/zen-browser/desktop/security/advisories/GHSA-qpj9-m8jc-mw6q
Remediation
No remediation data recorded yet
Check vendor advisories and the NVD entry for patch availability.