CVE-2026-49458

MEDIUM 6.1

DOMPurify: Cross-realm IN_PLACE sanitization leaves executable markup intact via realm-bound `instanceof` checks

CVSS Score

6.1

EPSS Score

0.0%

EPSS Percentile

0th

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.

CWE	CWE-79 CWE-501 CWE-693
Vendor	cure53
Product	dompurify
Published	Jul 14, 2026
Last Updated	Jul 15, 2026

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CVSS v3 Breakdown

CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:L/A:N

Attack Vector

Network

Attack Complexity

Low

Privileges Required

None

User Interaction

Required

Scope

Changed

Confidentiality

Low

Integrity

Low

Availability

None

Affected Versions

cure53 / DOMPurify

< 3.4.6

References

NVD ↗ CVE.org ↗ EPSS Data ↗

github.com: https://github.com/cure53/DOMPurify/security/advisories/GHSA-hpcv-96wg-7vj8 github.com: https://github.com/cure53/DOMPurify/commit/bb7739e5bccec7e1ab3dae3f3e42d02db3acaaae github.com: https://github.com/cure53/DOMPurify/releases/tag/3.4.6