{"cve":"CVE-2026-66010","nvd":{"published":"2026-07-24T13:18:28.720","modified":"2026-10-24T13:10:00.147","status":"Analyzed","description":"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.","cvss_v4":{"vector":"CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:A/VC:N/VI:N/VA:N/SC:L/SI:L/SA:N","score":5.1},"cvss_v3":{"version":"3.1","vector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:L/A:N","score":6.1},"cwes":["CWE-79"],"references":["https://github.com/cure53/DOMPurify/security/advisories/GHSA-c2j3-45gr-mqc4","https://www.vulncheck.com/advisories/dompurify-before-hook-bypass-via-custom-element-handling","https://github.com/cure53/DOMPurify/security/advisories/GHSA-c2j3-45gr-mqc4"],"products":["cure53:dompurify"],"source":"nvd","synced_at":"2026-10-24T16:53:27.712498749+00:00"},"epss":{"cve":"CVE-2026-66010","score":0.00215,"percentile":0.11828,"date":"2026-10-25"},"kev":null,"osv":[{"id":"GHSA-c2j3-45gr-mqc4","url":"https://osv.dev/vulnerability/GHSA-c2j3-45gr-mqc4","summary":"DOMPurify: `CUSTOM_ELEMENT_HANDLING` bypasses `afterSanitizeElements` for allowed custom elements.","modified":"2026-10-02T23:00:15.983015754Z","packages":[{"ecosystem":"npm","name":"dompurify","purl":"pkg:npm/dompurify","ranges":["<3.4.12"],"fixed":["3.4.12"]}]}],"attribution":["This product uses the NVD API but is not endorsed or certified by the NVD.","EPSS scores: FIRST Exploit Prediction Scoring System, https://www.first.org/epss","Known exploited vulnerabilities: CISA Known Exploited Vulnerabilities Catalog, https://www.cisa.gov/known-exploited-vulnerabilities-catalog","Package advisories: OSV (https://osv.dev), from the GitHub Advisory Database, PyPA, Go, RustSec and other ecosystem databases, under CC-BY 4.0 or CC0","CVE records: the CVE Program's CVE List (https://www.cve.org), under its terms of use (https://www.cve.org/Legal/TermsOfUse). CVE is a registered trademark of The MITRE Corporation; this product is not affiliated with the CVE Program."]}