Improper isolation or compartmentalization in Mozilla Firefox and Firefox for Android - CVE-2026-109750
Published: October 16, 2026
Vulnerability identifier: #VU156062
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-2026-109750
CWE-ID: CWE-653
Exploitation vector: Remote access
Exploit availability:
No public exploit available
Vulnerability details
The vulnerability allows a remote attacker to bypass site-isolation restrictions and potentially access resources outside the intended site boundary.
The vulnerability exists due to insufficient compartmentalization in the DOM: Web Authentication component when handling web-authentication operations. A remote attacker can trigger operations that cross an improperly enforced site boundary to bypass isolation and potentially access resources belonging to another site.
Affected software
Mozilla Firefox
Firefox for Android
Firefox for Android
How to mitigate CVE-2026-109750
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