Vulnerability · Published May 11, 2026 · Assigned by GitHub_M

CVE-2026-44658Zen Browser: RSS Live-Folder Item URLs Are Not Scheme-Restricted Before Trusted Tab Creation

Low 2.4

In plain English

A low-severity improper input validation in desktop from zen-browser. There are no confirmed reports of exploitation so far. The chance it is exploited in the next 30 days is estimated at 0.2% (higher than 5% of all known vulnerabilities).

Severity (CVSS 3.1)2.4Low

Exploit odds (30 days)0.2%top 95.1% of all CVEs

Exploited in the wildNo reportsCISA SSVC: none

Attack toolingNoneno public tooling known

Official description

Zen is a firefox-based browser. Prior to 1.19.12b, RSS feed URLs entered by the user are validated to http: or https: in promptForFeedUrl, but item links inside the feed are not subject to the same restriction. The provider maps each RSS/Atom item link into item.url, filters only for presence and date, and returns the item list. The live-folder manager later creates pinned lazy tabs from these values with gBrowser.addTrustedTab(item.url, ...). This vulnerability is fixed in 1.19.12b.

Affected products (as reported)

Vendor	Product	Versions
zen-browser	desktop	< 1.19.12b

Weakness: CWE-20 · Vector: CVSS:3.1/AV:N/AC:L/PR:H/UI:R/S:U/C:N/I:L/A:N

References

https://github.com/zen-browser/desktop/security/advisories/GHSA-cc9c-mmmf-c5j6 x_refsource_CONFIRM