Origin validation error in Mozilla Firefox and Firefox for Android - CVE-2026-109772
Published: October 16, 2026
Vulnerability identifier: #VU156068
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-2026-109772
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 resources belonging to another origin.
The vulnerability exists due to improper enforcement of origin restrictions in the DevTools component when handling developer-tool operations. A remote attacker can trigger operations that evade origin checks to cross an intended origin boundary and potentially access otherwise restricted resources.
Affected software
Mozilla Firefox
Firefox for Android
Firefox for Android
How to mitigate CVE-2026-109772
Install security update from vendor's website.
Mozilla Firefox - update to 158.0
Firefox for Android - update to 158.0
Firefox for Android - update to 158.0