Improper access control in Mozilla products - CVE-2026-100809
Published: September 29, 2026
Vulnerability identifier: #VU152849
CSH Severity: Medium
CVSS v4: 5.1 [CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:A/VC:L/VI:L/VA:N/SC:N/SI:N/SA:N]
CVE-ID: CVE-2026-100809
CWE-ID: CWE-284
Exploitation vector: Remote access
Exploit availability:
No public exploit available
Vulnerability details
The vulnerability allows a remote attacker to bypass the same-origin policy.
The vulnerability exists due to improper access control in the DevTools component when the component is used. A remote attacker can interact with the affected component to bypass the same-origin policy.
Affected software
Mozilla Firefox
Firefox ESR
Firefox for Android
Firefox ESR
Firefox for Android
How to mitigate CVE-2026-100809
Install security update from vendor's website.
Mozilla Firefox - update to 157.0
Firefox for Android - update to 157.0
Firefox ESR - update to 153.4.0
Firefox for Android - update to 157.0
Firefox ESR - update to 153.4.0