What’s Vulnerable › Vulnerabilities
CVE-2026-73492: Loofah `allowed_uri?` does not detect `javascript:` URIs split by numeric character references without semicolons
- Severity: low (CVSS 2.3 v4.0)
- Exploited in the wild: not listed in CISA KEV
- EPSS: 0.4% probability of exploitation in the next 30 days
- Public exploit or detection template: none known
- Published: 2026-08-12 · updated 2026-10-24
- Weakness: CWE-79
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: or vbscript: URIs whose scheme is split by semicolon-less numeric character references such as :, 	, 
, or 
. CGI.unescapeHTML leaves these references encoded, so allowed_uri? reports the URL safe even though a browser decodes an encoded colon or strips encoded whitespace and executes the resulting URI scheme. 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.
Affected products
- flavorjones loofah: from 2.25.0, < 2.25.2
References
- https://github.com/flavorjones/loofah/commit/f1be9d893b5a8dd79240441a912d8897e74c38c0
- 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-5qhf-9phg-95m2
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