CVE-2025-13018 is a mitigation bypass vulnerability in the DOM security component affecting Firefox versions prior to 145 and Firefox ESR versions prior to 140.5. It was assigned a CVSS score of 8.1, indicating high severity. The vulnerability allows bypassing security mitigations within the DOM, potentially impacting confidentiality and integrity. Mozilla has fixed this issue in Firefox 145 and Firefox ESR 140.5.