CVE-2026-116802

DOMPurify before 3.4.17 XSS via SMIL attributeName Guard Bypass in XHTML Mode

State: Published
Severity: 5.1 Medium
Published: Oct 26, 2026
Updated: Oct 26, 2026
Reserved: Oct 26, 2026

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.

Scores

CVSS	Score	Vector	Source
4.0	5.1 Medium	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	VulnCheck
3.1	6.1 Medium	CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:L/A:N	VulnCheck

Weaknesses

CWE-79 Improper Neutralization of Input During Web Page Generation ('Cross-site Scripting')

Affected Products

Product	Versions
DOMPurifycure53	before 3.4.17Affected 3.4.17Not affected

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 Modethird-party-advisory

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