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Vulnerability record · CVE-2026-66010 · published 24 July 2026

CVE-2026-66010: Cure53 dompurify cross-site scripting vulnerability

Cure53 · Dompurify

DOMPurify before 3.4.12 fails to execute afterSanitizeElements hook for custom elements allowed via CUSTOM_ELEMENT_HANDLING.tagNameCheck, allowing attributes to bypass application security policies. Attackers can preserve sensitive attributes on custom elements that later re-inject them into innerHTML sinks, creating second-order XSS gadgets.

5.1 CVSS 4.0 Medium EPSS 0.31% · top 79.2% CWE-79 · Cross-site scripting
5.1CVSS 4.0 base score
0.31%EPSS exploitation probability, 30 days
NoNot in CISA KEV
1Affected product versions listed by NVD
3References, 2 tagged exploit
6 Aug 2026Last modified by NVD

Description

DOMPurify before 3.4.12 fails to execute afterSanitizeElements hook for custom elements allowed via CUSTOM_ELEMENT_HANDLING.tagNameCheck, allowing attributes to bypass application security policies. Attackers can preserve sensitive attributes on custom elements that later re-inject them into innerHTML sinks, creating second-order XSS gadgets.

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/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:

Affected products

1 vulnerable configurations from NVD's CPE data, grouped by vendor and product.

References

LinkTags
https://github.com/cure53/DOMPurify/security/advisories/GHSA-c2j3-45gr-mqc4 ExploitVendor Advisory
https://www.vulncheck.com/advisories/dompurify-before-hook-bypass-via-custom-element-handling Third Party Advisory
https://github.com/cure53/DOMPurify/security/advisories/GHSA-c2j3-45gr-mqc4 ExploitVendor Advisory

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Related vulnerabilities

Same products first, then exploited flaws of the same weakness class.

9.8CVE-2024-48910Cure53 dompurify prototype pollution vulnerabilityDOMPurify is a DOM-only, super-fast, uber-tolerant XSS sanitizer for HTML, MathML and SVG. DOMPurify was vulnerable to prototype pollution. This vuln…EPSS 1.2%8.2CVE-2026-47423Cure53 dompurify cross-site scripting vulnerabilityDOMPurify is a DOM-only cross-site scripting sanitizer for HTML, MathML, and SVG. In 3.4.4, DOMPurify allowed selectedcontent by default, allowing br…EPSS 0.41%6.3CVE-2026-49978Cure53 dompurify cross-site scripting vulnerabilityDOMPurify is a DOM-only cross-site scripting sanitizer for HTML, MathML, and SVG. Prior to 3.4.7, DOMPurify IN_PLACE sanitization could skip shadow c…EPSS 0.40%6.1CVE-2026-49458Cure53 dompurify cross-site scripting vulnerabilityDOMPurify is a DOM-only cross-site scripting sanitizer for HTML, MathML, and SVG. Prior to 3.4.6, DOMPurify.sanitize(node, { IN_PLACE: true }) accept…EPSS 0.40%6.1CVE-2026-49459Cure53 dompurify cross-site scripting vulnerabilityDOMPurify is a DOM-only cross-site scripting sanitizer for HTML, MathML, and SVG. Prior to 3.4.6, DOMPurify.sanitize(root, { IN_PLACE: true }) could …EPSS 0.37%6.1CVE-2025-26791Cure53 dompurify cross-site scripting vulnerabilityDOMPurify before 3.2.4 has an incorrect template literal regular expression, sometimes leading to mutation cross-site scripting (mXSS).EPSS 0.61%6.1CVE-2024-47875Cure53 dompurify cross-site scripting vulnerabilityDOMPurify is a DOM-only, super-fast, uber-tolerant XSS sanitizer for HTML, MathML and SVG. DOMpurify was vulnerable to nesting-based mXSS. This vulne…EPSS 1.1%6.1CVE-2024-45801Cure53 dompurify inefficient regular expression (redos) vulnerabilityDOMPurify is a DOM-only, super-fast, uber-tolerant XSS sanitizer for HTML, MathML and SVG. It has been discovered that malicious HTML using special n…EPSS 0.89%

Source: NIST National Vulnerability Database (record CVE-2026-66010), CISA KEV, FIRST EPSS (scores of 2026-09-28). This page is refreshed as NVD updates the record.