Vulnerability Description
Loofah is a general library for manipulating and transforming HTML/XML documents and fragments, built on top of Nokogiri. From 2.25.0 until 2.25.2, Loofah::HTML5::Scrub.allowed_uri? does not reject javascript: URIs whose scheme is split or prefixed with the HTML5 named whitespace character references 	 or 
. CGI.unescapeHTML leaves those references intact, so allowed_uri? reports the URL safe even though a browser decodes and strips the tab or line feed and executes the resulting javascript: URL. This issue affects only callers that pass HTML-encoded strings directly to allowed_uri?; Loofah's default sanitize() path is not affected. This issue is fixed in version 2.25.2.
Related Weaknesses (CWE)
References
- https://github.com/flavorjones/loofah/commit/5e91af861e3cdab47b91dd0b81f3afdfd13
- https://github.com/flavorjones/loofah/pull/308
- https://github.com/flavorjones/loofah/releases/tag/v2.25.2
- https://github.com/flavorjones/loofah/security/advisories/GHSA-8whx-365g-h9vv
FAQ
What is CVE-2026-73491?
CVE-2026-73491 is a documented vulnerability. Loofah is a general library for manipulating and transforming HTML/XML documents and fragments, built on top of Nokogiri. From 2.25.0 until 2.25.2, Loofah::HTML5::Scrub.allowed_uri? does not reject ja...
How severe is CVE-2026-73491?
CVSS scoring is not yet available for CVE-2026-73491. Check NVD for updates.
Is there a patch for CVE-2026-73491?
Check the references section above for vendor advisories and patch information. Review vendor security bulletins for remediation guidance.