CVE-2026-73491 (Medium) detected in loofah-2.25.1.gem

Nobody has claimed this yet.

## CVE-2026-73491 - Medium Severity Vulnerability
Vulnerable Library - loofah-2.25.1.gem

Loofah is a general library for manipulating and transforming HTML/XML documents and fragments,
built on top of Nokogiri.

Loofah also includes some HTML sanitizers based on `html5lib`'s safelist, which are a specific
application of the general transformation functionality.

Library home page: https://rubygems.org/gems/loofah-2.25.1.gem

Sample Path to Dependency File: /Gemfile.lock

Path to vulnerable library: /tmp/containerbase/cache/.ruby/cache/loofah-2.25.1.gem

Dependency Hierarchy:
- rails-8.0.5.gem (Root Library)
- activestorage-8.0.5.gem
- actionpack-8.0.5.gem
- actionview-8.0.5.gem
- rails-html-sanitizer-1.7.0.gem
- :x: **loofah-2.25.1.gem** (Vulnerable Library)

Found in base branch: master

Vulnerability Details

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.
Mend Note: The description of this vulnerability differs from MITRE.

Publish Date: 2026-08-12

URL: CVE-2026-73491

CVSS 3 Score Details (4.9)

Base Score Metrics:
- Exploitability Metrics:
- Attack Vector: Network
- Attack Complexity: High
- Privileges Required: Low
- User Interaction: None
- Scope: Changed
- Impact Metrics:
- Confidentiality Impact: Low
- Integrity Impact: Low
- Availability Impact: None

For more information on CVSS3 Scores, click here.

Suggested Fix

Type: Upgrade version

Release Date: 2026-08-12

Fix Resolution: https://github.com/flavorjones/loofah.git - v2.25.2

***
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Start with Gemfile.lock and the dependency hierarchy shown in the issue, tracing rails through rails-html-sanitizer to loofah. Update the resolved Loofah dependency to 2.25.2, then verify the lockfile no longer contains 2.25.1 and rerun the project's dependency or security scan to confirm the vulnerability is resolved.

Written by the indexing model from the issue text.