CVE-2026-73491
Loofah is a general library for manipulating and transforming HTML/XML documents and fragments, built on top of Nokogiri.
Overview
CVE-2026-73491 is a known-severity vulnerability. It was published on August 12, 2026.
Technical 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.
Remediation
Check the references section for vendor advisories, patches, and mitigation guidance. If immediate patching is not possible, review the CVSS vector to understand the attack surface and apply compensating controls such as network segmentation or access restrictions.
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Frequently asked questions
What is CVE-2026-73491?
CVE-2026-73491 is a known-severity vulnerability. It was published on August 12, 2026.
How severe is CVE-2026-73491?
CVSS score information is not yet available for this vulnerability. Check back as the CVE record is updated by NVD analysts.
How do I fix or remediate CVE-2026-73491?
Check the references section for vendor advisories, patches, and mitigation guidance. If immediate patching is not possible, review the CVSS vector to understand the attack surface and apply compensating controls such as network segmentation or access restrictions.
How can CyberStrike help with CVE-2026-73491?
CyberStrike is an open-source, AI-augmented pentesting engine. Rather than flag a version number, it tests whether an issue like CVE-2026-73491 is actually reachable in your own applications and APIs, then verifies each finding before reporting it. That tells you if the weakness is a real, exploitable risk in your environment or a false positive you can safely deprioritize.