AIKIDO-2026-349881
loofah is vulnerable to Cross-site Scripting (XSS)
25
Low Risk
This Affects:
loofahTL;DR
Affected versions of loofah are vulnerable to Cross-site Scripting (XSS) via a bypass in Loofah::HTML5::Scrub.allowed_uri?. The helper does not reject javascript: or vbscript: URIs when the scheme is split by numeric character references without a trailing semicolon (e.g. javascript:alert(1) or java	script:alert(1)). CGI.unescapeHTML leaves those forms undecoded, so scheme detection fails and the method returns true, while browsers decode them and execute the URI. This bypasses the prior fix for GHSA-46fp-8f5p-pf2m, which only covered references with a trailing ;.
Who does this affect?
You are affected if you are using a version that falls within the vulnerable range and call Loofah::HTML5::Scrub.allowed_uri? (directly or via higher-level features such as Action Text markdown link validation) with HTML-encoded URI strings. The default sanitize() path is not affected.
Background info
loofah is vulnerable to Cross-site Scripting (XSS) in versions 2.25.0 - 2.25.1.
How to fix this
Upgrade the loofah library to the patch version.
Are You Affected?
Connect your repositories to instantly see whether vulnerable or malicious packages exist in your codebase.
Free. No credit card required.
I consent to receiving marketing communications based on Aikido’s Privacy Policy.
SOC 2Compliant
ISO 27001Compliant