{"id":"CVE-2026-61784","aliases":["GHSA-j8r4-32c5-33rc"],"url":"https://o3.security/vulnerability/CVE-2026-61784","summary":"xhtml-purifier has HTML attribute-injection (sanitizer bypass) that leads to XSS","details":"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.","published":"2026-09-24T17:35:57.096Z","modified":"2026-10-21T02:58:53.013777750Z","cvss":{"score":6.1,"severity":"MEDIUM","vector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:L/A:N"},"epss":null,"cisaKev":null,"exploitsKnown":null,"affectedPackages":[{"ecosystem":"npm","name":"xhtml-purifier","fixedVersion":"0.4.3"}],"fix":{"url":"https://github.com/cstigler/node-xhtml-purifier/commit/21d461ad23e7bc9b3073693d5b51b9b8662044d3","label":"cstigler/node-xhtml-purifier@21d461a"},"references":[{"type":"ADVISORY","url":"https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/61xxx/CVE-2026-61784.json"},{"type":"ADVISORY","url":"https://github.com/cstigler/node-xhtml-purifier/security/advisories/GHSA-j8r4-32c5-33rc"},{"type":"ADVISORY","url":"https://nvd.nist.gov/vuln/detail/CVE-2026-61784"},{"type":"FIX","url":"https://github.com/cstigler/node-xhtml-purifier/commit/21d461ad23e7bc9b3073693d5b51b9b8662044d3"},{"type":"WEB","url":"https://github.com/cstigler/node-xhtml-purifier/pull/6"},{"type":"PACKAGE","url":"https://github.com/cstigler/node-xhtml-purifier"},{"type":"WEB","url":"https://github.com/cstigler/node-xhtml-purifier/releases/tag/v0.4.3"}],"provenance":{"sources":["OSV.dev","FIRST.org (EPSS)"],"lastVerified":"2026-10-21T02:58:53.013777750Z"}}