Incorrect calculation in Mozilla Firefox and Firefox for Android - CVE-2026-12321
Published: June 16, 2026
Vulnerability identifier: #VU134643
CSH Severity: Low
CVSS v4.0: CVSS:4.0/AV:L/AC:L/AT:N/PR:N/UI:A/VC:N/VI:N/VA:L/SC:N/SI:N/SA:N/E:U/U:Clear
CVE-ID: CVE-2026-12321
CWE-ID: CWE-682
Exploitation vector: Remote access
Exploit availability:
No public exploit available
Vendor: Mozilla
Affected software:
Mozilla Firefox
Firefox for Android
Mozilla Firefox
Firefox for Android
Detailed vulnerability description
The vulnerability allows a remote attacker to cause a denial of service.
The vulnerability exists due to JIT miscompilation in the JavaScript: WebAssembly component when executing WebAssembly code. A remote attacker can supply crafted WebAssembly code to cause a denial of service.
How to mitigate CVE-2026-12321
Install security update from vendor's website.