CVE-2026-49458
DOMPurify: Cross-realm IN_PLACE sanitization leaves executable markup intact via realm-bound `instanceof` checks
MEDIUM 6.1EPSS 0.4%
DOMPurify is a DOM-only cross-site scripting sanitizer for HTML, MathML, and SVG. Prior to 3.4.6, DOMPurify.sanitize(node, { IN_PLACE: true }) accepted same-origin foreign-realm DOM nodes while follow-on checks used parent-realm constructors, causing instanceof checks for forms, named node maps, document fragments, and elements to fail and skip clobber, template-content, and shadow-DOM sanitization branches so executable markup could survive. This issue is fixed in version 3.4.6.
- Affected
- cure53 · DOMPurify
- CVSS v3.1 GITHUB
- 6.1 MEDIUM
CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:L/A:N - EPSS
- 0.40% chance of exploitation in the next 30 days, 33rd percentile
- Published
- 2026-07-14
- Updated
- 2026-07-15
Proof-of-concept exploits (1)
Security advisories
- cure53/DOMPurify/security/advisories/GHSA-hpcv-96wg-7vj8
- cure53/DOMPurify/commit/bb7739e5bccec7e1ab3dae3f3e42d02db3acaaae