PT-2026-39659 · Zen Browser · Rdesktop

Published 2026-05-11 · Updated 2026-05-11 · CVE-2026-41431

Mitre

CVSS v3.1

8.0

High

Base vector

AV:N/AC:H/PR:H/UI:N/S:C/C:H/I:H/A:H

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.

Fix

Improper Verification of Cryptographic Signature

Weakness Enumeration

CWE-347

Related Identifiers

CVE-2026-41431

Affected Products

Rdesktop

References · 3

• https://nvd.nist.gov/vuln/detail/CVE-2026-41431 · Security Note
• https://github.com/zen-browser/desktop/security/advisories/GHSA-qpj9-m8jc-mw6q · Note
• https://github.com/zen-browser/desktop/commit/270db6d6713d2c6c14d9df0b4bc7662843d3d54e · Note