Vulnerability Description
xhtml-purifier is a Node.js library to take in raw/unknown/untrusted HTML and output cleaned, purified, trusted HTML. Versions prior to 0.4.3 do not HTML-entity-encode attribute values when serializing its sanitized output. In attributeString() (XHTMLPurifier.js, around line 148) the attribute value is concatenated directly into a double-quoted attribute without encoding. As a result, an attacker-controlled value in any allowed attribute (class, style, title, alt, src, href) can include a double-quote character to break out of the attribute and inject an additional attribute, such as a JavaScript event handler (for example onmouseover or onerror). The injected handler survives sanitization and executes when the output is rendered, which is a sanitizer bypass leading to cross-site scripting. The fix in version 0.4.3 HTML-entity-encodes attribute values before serialization.
CVSS Score
MEDIUM
Related Weaknesses (CWE)
References
- https://github.com/cstigler/node-xhtml-purifier/commit/21d461ad23e7bc9b3073693d5
- https://github.com/cstigler/node-xhtml-purifier/security/advisories/GHSA-j8r4-32
FAQ
What is CVE-2026-61784?
CVE-2026-61784 is a vulnerability with a CVSS score of 6.1 (MEDIUM). xhtml-purifier is a Node.js library to take in raw/unknown/untrusted HTML and output cleaned, purified, trusted HTML. Versions prior to 0.4.3 do not HTML-entity-encode attribute values when serializin...
How severe is CVE-2026-61784?
CVE-2026-61784 has been rated MEDIUM with a CVSS base score of 6.1/10. Review the CVSS metrics above for detailed severity breakdown.
Is there a patch for CVE-2026-61784?
Check the references section above for vendor advisories and patch information. Review vendor security bulletins for remediation guidance.