[ CVE-2026-61784 · Published 24 Sep 2026 ]
xhtml-purifier has HTML attribute-injection (sanitizer bypass) that leads to XSS
[ Description ]Official 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.
[ Fixes ]Fixes and patches
- xhtml-purifier 0.4.3Fixed version · GitHub Advisories · npm package xhtml-purifier: upgrade to 0.4.3 or later (affected <= 0.4.1)
[ Packages ]Affected open-source packages
- xhtml-purifier npmAffected <= 0.4.1 · fixed in 0.4.3 · GHSA-j8r4-32c5-33rc