Protection mechanism failure in Mozilla products - CVE-2026-0877
Published: January 13, 2026
Vulnerability identifier: #VU121207
CSH Severity: High
CVSS v4.0: CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:A/VC:H/VI:H/VA:N/SC:N/SI:N/SA:N/E:U/U:Amber
CVE-ID: CVE-2026-0877
CWE-ID: CWE-693
Exploitation vector: Remote access
Exploit availability:
No public exploit available
Vendor: Mozilla
Affected software:
Firefox ESR
Mozilla Firefox
Firefox for Android
Firefox ESR
Mozilla Firefox
Firefox for Android
Detailed vulnerability description
The vulnerability allows a remote attacker to bypass implemented security restrictions.
The vulnerability exists due to insufficient implementation of security measures. An attacker can bypass implemented DOM security restrictions and execute arbitrary JavaScript code.
How to mitigate CVE-2026-0877
Install updates from vendor's website.