CVE-2026-44658CWE-20

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

Low · published May 11, 2026

CVSS v3.1
2.4
EPSS
0%
Percentile
17.8
In the wild
Unconfirmed
What it is

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.

The record
Technical detail
CVSS v3.1
2.4 · LOW
Vector
CVSS:3.1/AV:N/AC:L/PR:H/UI:R/S:U/C:N/I:L/A:N
CVSS v4.0
Not supplied
EPSS
0.00267 · 17.8th percentile
Weakness
CWE-20 · Improper Input Validation
Published
2026-05-11T17:00Z
EPSS history
Timeline
  • 11 MAY 17:00Z
    Zen Browser: RSS Live-Folder Item URLs Are Not Scheme-Restricted Before Trusted Tab Creation
    cvelistv5