Origin validation error in Mozilla Firefox and Firefox for Android - CVE-2026-124950
Published: November 10, 2026
Vulnerability identifier: #VU164588
CSH Severity: Medium
CVSS v4: 5.1 [CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:A/VC:L/VI:N/VA:N/SC:N/SI:N/SA:N]
CVE-ID: CVE-2026-124950
CWE-ID: CWE-346
Exploitation vector: Remote access
Exploit availability:
No public exploit available
Vulnerability details
The vulnerability allows a remote attacker to bypass the same-origin policy and potentially access cross-origin information.
The vulnerability exists due to improper origin enforcement in Firefox's CSS Parsing and Computation component when processing stylesheets. A remote attacker can supply crafted CSS to bypass origin restrictions and potentially access information belonging to another origin.
Affected software
Mozilla Firefox
Firefox for Android
Firefox for Android
How to mitigate CVE-2026-124950
Install security update from vendor's website.
Mozilla Firefox - update to 160.0
Firefox for Android - update to 160.0
Firefox for Android - update to 160.0