CVE-2025-13013 is a mitigation bypass vulnerability in the DOM Core & HTML component affecting Firefox versions prior to 145 and Firefox ESR versions prior to 140.5 and 115.30. The vulnerability allows bypassing security mitigations in the browser's DOM implementation. It has a CVSS score of 6.1, indicating a medium severity impact with potential confidentiality and integrity loss but no availability impact. Mozilla has fixed this issue in Firefox 145 and Firefox ESR 140.5.