CVE-2026-73492

Loofah `allowed_uri?` does not detect `javascript:` URIs split by numeric character references without semicolons

State: Published
Severity: 2.3 Low
Published: Aug 12, 2026
Updated: Aug 14, 2026
Reserved: Aug 12, 2026

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 &#58, &#9, &#10, or &#13. 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.

Scores

CVSS	Score	Vector	Source
4.0	2.3 Low	CVSS:4.0/AV:N/AC:H/AT:N/PR:L/UI:N/VC:N/VI:N/VA:N/SC:L/SI:L/SA:N	GitHub_M

Weaknesses

CWE-79 Improper Neutralization of Input During Web Page Generation ('Cross-site Scripting')
CWE-184 Incomplete List of Disallowed Inputs

Affected Products

Product	Versions
loofahflavorjones	>= 2.25.0, < 2.25.2Affected

References

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