What’s Vulnerable › Vulnerabilities

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

• Severity: medium (CVSS 6.1 v3.1)
• Exploited in the wild: not listed in CISA KEV
• EPSS: 0.2% probability of exploitation in the next 30 days
• Public exploit or detection template: none known
• Published: 2026-10-26 · updated 2026-10-27
• Weakness: CWE-79

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 products

• Npm Dompurify: before 3.4.17 — fixed in 3.4.17
• cure53 DOMPurify: before 3.4.17 — fixed in 3.4.17

How to fix

Upgrade to a fixed version: Npm Dompurify 3.4.17; cure53 DOMPurify 3.4.17. Check the vendor advisory for mitigations.

References

• https://github.com/cure53/DOMPurify/security/advisories/GHSA-c6gr-qvv4-5v3f
• https://www.vulncheck.com/advisories/dompurify-before-3.4.17-xss-via-smil-attributename-guard-bypass-in-xhtml-mode

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