CVE-2026-61784
xhtml-purifier is a Node.js library to take in raw/unknown/untrusted HTML and output cleaned, purified, trusted HTML.
Impact
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.
Affected packages
| Ecosystem | Package | Affected | Fixed in |
|---|---|---|---|
| npm | xhtml-purifier | <= 0.4.1 | 0.4.3 |
Weakness classification
References
- NVD record
- CVE.org record
- GitHub advisory
- https://github.com/advisories/GHSA-j8r4-32c5-33rc
- https://github.com/cstigler/node-xhtml-purifier/security/advisories/GHSA-j8r4-32c5-33rc
- https://nvd.nist.gov/vuln/detail/CVE-2026-61784
- https://github.com/cstigler/node-xhtml-purifier/pull/6
- https://github.com/cstigler/node-xhtml-purifier/commit/21d461ad23e7bc9b3073693d5b51b9b8662044d3
- https://github.com/cstigler/node-xhtml-purifier/releases/tag/v0.4.3