{"id":"CVE-2026-66010","aliases":["GHSA-c2j3-45gr-mqc4"],"url":"https://o3.security/vulnerability/CVE-2026-66010","summary":"DOMPurify before 3.4.12 Hook Bypass via CUSTOM_ELEMENT_HANDLING","details":"DOMPurify before 3.4.12 fails to execute afterSanitizeElements hook for custom elements allowed via CUSTOM_ELEMENT_HANDLING.tagNameCheck, allowing attributes to bypass application security policies. Attackers can preserve sensitive attributes on custom elements that later re-inject them into innerHTML sinks, creating second-order XSS gadgets.","published":"2026-07-24T12:07:57.374Z","modified":"2026-08-12T03:51:08.903946641Z","cvss":null,"epss":{"score":0.00215,"percentile":0.11869,"asOf":"2026-09-06"},"cisaKev":null,"exploitsKnown":0,"affectedPackages":[{"ecosystem":"npm","name":"dompurify","fixedVersion":"3.4.12"}],"fix":null,"references":[{"type":"ADVISORY","url":"https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/66xxx/CVE-2026-66010.json"},{"type":"ADVISORY","url":"https://github.com/cure53/DOMPurify/security/advisories/GHSA-c2j3-45gr-mqc4"},{"type":"ADVISORY","url":"https://nvd.nist.gov/vuln/detail/CVE-2026-66010"},{"type":"ADVISORY","url":"https://www.vulncheck.com/advisories/dompurify-before-hook-bypass-via-custom-element-handling"}],"provenance":{"sources":["OSV.dev","FIRST.org (EPSS)"],"lastVerified":"2026-08-12T03:51:08.903946641Z"}}