CVE-2026-124866 is a use-after-free vulnerability in the Layout component of Firefox. This flaw was addressed and fixed in Firefox version 160 and Firefox ESR 153.7. The vulnerability has a high severity rating with a CVSS score of 8.8, indicating it could allow an attacker to cause a crash or potentially execute arbitrary code. No known exploits in the wild have been reported. Users should update to the fixed versions to mitigate this issue.