Quick answers
- Is CVE-2026-41431 exploited in the wild?
- No. Junglewise Threat Intelligence has no report of CVE-2026-41431 being exploited in the wild.
- How severe is CVE-2026-41431?
- High severity, with a CVSS score of 8, published 11 May 2026.
- Which products and versions are affected?
- Zen Browser Prior to 1.19.9b.
- Is there a fix for CVE-2026-41431?
- A patch was published on 2026-04-09: Fix committed to repository Junglewise finds every place you run it, drafts the upgrade and applies it once you approve.
- How is CVE-2026-41431 attacked?
- It is attacked over the network, in a network appliance.
- Am I affected by CVE-2026-41431?
- Check whether you run Zen Browser at an affected version. Junglewise does that check for you around the clock: connect your code, cloud and domains, and it matches new vulnerabilities like this one against what you actually run and tells you when one reaches you.
Technical details
Zen Browser (prior to 1.19.9b) was found to have stripped Mozilla Application Resource (MAR) signature verification code from its updater component (org.mozilla.updater). Analysis of the updater binary revealed that cryptographic symbols for signature verification were missing and replaced with a 'Not Applicable' string, while the MAR update files themselves contained zero signatures. While the browser performs a SHA-512 integrity check against an XML manifest, both the manifest and the update file originate from the same trust domain. Consequently, a compromise of the update server or the GitHub release pipeline would allow an attacker to distribute arbitrary unsigned code to users. The issue was resolved in version 1.19.9b by re-enabling MAR signature verification and implementing a proper signing infrastructure.
Affected products
- Zen Browser Zen Browser Prior to 1.19.9b
Timeline
- 2026-04-09: patched: Fix committed to repository
- 2026-04-24: advisory: GitHub Security Advisory published
- 2026-05-11: disclosed: CVE published to NVD