CVE-2026-73491

LOW

Loofah `allowed_uri?` does not detect `javascript:` URIs split by named whitespace character references

Title source: CVE List
STIX 2.1 vulnerability

Record summary

CVE-2026-73491 has a selected CVSS score of 2.3 (low).

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.

Description source: CVE List

Exploitation context

CISA SSVC decision

ExploitationNone
AutomatableNo
Technical impactPartial

CISA Coordinator · SSVC 2.0.3 · Evaluated Aug 13, 2026 · Source: CVE List

Affected products and versions

2
ProductSourceVersion range

loofah

Browse flavorjones / loofah
CVE List>= 2.25.0, < 2.25.2affected

loofah

Browse RubyGems / loofah
GitHub Advisory2.25.0 to < 2.25.2 · Fixed in 2.25.2affected

References

5