Vulnerability · Published Oct 26, 2026 · Assigned by VulnCheck

CVE-2026-116802DOMPurify before 3.4.17 XSS via SMIL attributeName Guard Bypass in XHTML Mode

Medium 6.1

In plain English

A medium-severity cross-site scripting in DOMPurify from cure53. Proof-of-concept exploit code is public. The chance it is exploited in the next 30 days is estimated at 0.2% (higher than 12% of all known vulnerabilities). Fixed versions are available - upgrade the affected package.

Severity (CVSS 3.1)6.1Medium

Exploit odds (30 days)0.2%top 87.8% of all CVEs

Exploited in the wildNo reportsCISA SSVC: poc

Attack toolingNoneno public tooling known

Official description

DOMPurify before 3.4.17 contains a cross-site scripting vulnerability that allows attackers to bypass the SMIL attributeName=href guard when PARSER_MEDIA_TYPE is application/xhtml+xml, because transformCaseFunc does not lowercase attribute names. Attackers can submit SVG with an animate or set element using attributeName="href" and a javascript: entry in values to execute script when users click the sanitized link.

Affected packages & fixed versions

Ecosystem	Package	Fixed in	Advisory
Debian:12	node-dompurify	no fix listed	DEBIAN-CVE-2026-116802
Debian:13	node-dompurify	no fix listed	DEBIAN-CVE-2026-116802
Debian:14	node-dompurify	3.4.17+dfsg-1	DEBIAN-CVE-2026-116802
Ubuntu:22.04:LTS	node-dompurify	no fix listed	UBUNTU-CVE-2026-116802
Ubuntu:24.04:LTS	node-dompurify	no fix listed	UBUNTU-CVE-2026-116802
Ubuntu:26.04:LTS	node-dompurify	no fix listed	UBUNTU-CVE-2026-116802
Ubuntu:26.10	node-dompurify	no fix listed	UBUNTU-CVE-2026-116802
npm	dompurify	3.4.17	GHSA-c6gr-qvv4-5v3f

Affected products (as reported)

Vendor	Product	Versions
cure53	DOMPurify	0 – before 3.4.17

Weakness: CWE-79 · Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:L/A:N

References

GitHub Security Advisory (GHSA-c6gr-qvv4-5v3f) vendor-advisory
VulnCheck Advisory: DOMPurify before 3.4.17 XSS via SMIL attributeName Guard Bypass in XHTML Mode third-party-advisory