Race condition in Mozilla products - CVE-2026-109776
Published: October 16, 2026
Vulnerability identifier: #VU156047
CSH Severity: Low
CVSS v4: 2.1 [CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:A/VC:N/VI:N/VA:L/SC:N/SI:N/SA:N]
CVE-ID: CVE-2026-109776
CWE-ID: CWE-362
Exploitation vector: Remote access
Exploit availability:
No public exploit available
Vulnerability details
The vulnerability allows a remote attacker to trigger inconsistent component state that may disrupt browser operation.
The vulnerability exists due to a race condition in the XPCOM component when coordinating concurrent operations. A remote attacker can trigger affected operations with conflicting timing to produce inconsistent state and potentially disrupt browser functionality.
Affected software
Firefox ESR
Mozilla Firefox
Firefox for Android
Debian Linux
firefox-esr (Debian package)
Mozilla Firefox
Firefox for Android
Debian Linux
firefox-esr (Debian package)
How to mitigate CVE-2026-109776
Install security update from vendor's website.
Firefox ESR - update to 153.5.0
Firefox for Android - update to 158.0
Mozilla Firefox - update to 158.0
firefox-esr (Debian package) - update to 153.5.0esr-1~deb13u1
Firefox for Android - update to 158.0
Mozilla Firefox - update to 158.0
firefox-esr (Debian package) - update to 153.5.0esr-1~deb13u1