CVE-2026-65904 | DOMPurify through 3.3.3 fails to sanitize DOM elements passe… | CVSS 4.7 MEDIUM

Description

DOMPurify through 3.3.3 fails to sanitize DOM elements passed via IN_PLACE mode when the element originates from a different window/realm (e.g., an iframe's contentDocument). A cross-realm instanceof check in the private _isNode() function returns false for foreign-realm nodes, causing DOMPurify to stringify the element (yielding '[object HTMLDivElement]'), silently reset IN_PLACE to false, and return the unsanitized element unchanged with any XSS payloads intact.

Metadata

CVE ID: CVE-2026-65904
State: PUBLISHED
Assigner: VulnCheck
Reserved: 2026-07-23 11:03 UTC
Published: 2026-07-23 13:16 UTC
Last updated: 2026-07-24 21:35 UTC
Primary CWE: CWE-754
Improper Check for Unusual or Exceptional Conditions
Vendor / Product: cure53 / DOMPurify
Sources: cve.org · NVD

Severity & Metrics

4.7 MEDIUM CVSS 3.1

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

SSVC — CISA Coordinator

Exploitation: PoC
Automatable: no
Tech. Impact: partial

Affected products (1)

Vendor	Product	Platform	Versions
cure53	DOMPurify	—	0 ≤ 3.3.3

Weakness (CWE)

CWE	Source	Description
CWE-754	cna	Improper Check for Unusual or Exceptional Conditions

CVSS scores (2)

Score	Severity	Version	Source	Vector
4.7	MEDIUM	3.1	cna	CVSS:3.1/AV:N/AC:H/PR:N/UI:R/S:C/C:L/I:L/A:N
2.3	LOW	4.0	cna	CVSS:4.0/AV:N/AC:H/AT:P/PR:N/UI:P/VC:N/VI:N/VA:N/SC:L/SI:L/SA:N

References (2)

GitHub Security Advisory (GHSA-4w3q-35jp-p934) https://github.com/cure53/DOMPurify/security/advisories/GHSA-4w3q-35jp-p934
VulnCheck Advisory: DOMPurify before 3.4.4 Cross-Site Scripting via IN_PLACE mode https://www.vulncheck.com/advisories/dompurify-before-cross-site-scripting-via-in-place-mode