Input validation error in Mozilla products - CVE-2026-124856
Published: November 10, 2026
Vulnerability identifier: #VU164520
CSH Severity: Low
CVSS v4: 5.1 [CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:A/VC:N/VI:N/VA:L/SC:N/SI:N/SA:N]
CVE-ID: CVE-2026-124856
CWE-ID: CWE-20
Exploitation vector: Remote access
Exploit availability:
No public exploit available
Vulnerability details
The vulnerability allows a remote attacker to trigger incorrect handling of boundary cases, potentially disrupting HTTP processing.
The vulnerability exists due to incorrect boundary conditions in the Networking: HTTP component when processing HTTP traffic. A remote attacker can supply input that reaches an incorrectly handled boundary case to potentially disrupt browser operation.
Affected software
Firefox ESR
Mozilla Firefox
Firefox for Android
Mozilla Firefox
Firefox for Android
How to mitigate CVE-2026-124856
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