Origin validation error in Mozilla products - CVE-2026-124931
Published: November 10, 2026
Vulnerability identifier: #VU164557
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-2026-124931
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, potentially accessing information across origin boundaries.
The vulnerability exists due to improper origin enforcement in the DOM: Core & HTML component when processing document content. A remote attacker can trigger affected cross-origin behavior to bypass origin restrictions and potentially access otherwise restricted information.
Affected software
Firefox ESR
Mozilla Firefox
Firefox for Android
Mozilla Firefox
Firefox for Android
How to mitigate CVE-2026-124931
Install security update from vendor's website.
Firefox ESR - update to 153.7.0
Firefox for Android - update to 160.0
Mozilla Firefox - update to 160.0
Firefox for Android - update to 160.0
Mozilla Firefox - update to 160.0