CVE-2026-73492: flavorjones loofah Cross-site Scripting

Vulnerability summary

CVE-2026-73492 is a low (CVSS 2.3) Cross-site Scripting vulnerability in flavorjones loofah. EPSS estimates a 0.39% chance of exploitation in the next 30 days, higher than 32.4% of scored vulnerabilities.

Timeline

1. 12-08-2026
   PublishedVulnerability first disclosed.
2. 14-08-2026
   Last modifiedVulnerability information updated.

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.

• CWE-79Improper Neutralization of Input During Web Page Generation ('Cross-site Scripting')The product does not neutralize or incorrectly neutralizes user-controllable input before it is placed in output that is used as a web page that is served to other users.
• CWE-184Incomplete List of Disallowed InputsThe product implements a protection mechanism that relies on a list of inputs (or properties of inputs) that are not allowed by policy or otherwise require other action to neutralize before additional processing takes place, but the list is incomplete.