#VU121207 Protection mechanism failure in Mozilla products - CVE-2026-0877
Published: January 13, 2026
Vulnerability identifier: #VU121207
Vulnerability risk: High
CVSSv4.0: 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
Vulnerable software:
Firefox ESR
Mozilla Firefox
Firefox for Android
Firefox ESR
Mozilla Firefox
Firefox for Android
Software vendor:
Mozilla
Mozilla
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.
Remediation
Install updates from vendor's website.