---
id: GHSA-9wjq-cp2p-hrgf
title: 'Loofah: SVG `href` attribute bypasses local-reference restriction'
summary: 'Loofah: SVG `href` attribute bypasses local-reference restriction'
severity: medium
cvss: 4.7
cwe:
  - CWE-79
vendor: loofah
product: loofah
ecosystem: rubygems
affected:
  - loofah < 2.25.2
patched:
  - loofah 2.25.2
published: '2026-07-21'
updated: '2026-07-21'
source: GHSA
sourceUrl: 'https://github.com/advisories/GHSA-9wjq-cp2p-hrgf'
references:
  - url: >-
      https://github.com/flavorjones/loofah/security/advisories/GHSA-9wjq-cp2p-hrgf
  - url: >-
      https://github.com/flavorjones/loofah/commit/20867b9be689521887364b74822c41ef830523c9
  - url: 'https://github.com/flavorjones/loofah/releases/tag/v2.25.2'
  - url: 'https://github.com/advisories/GHSA-9wjq-cp2p-hrgf'
tags:
  - ghsa
  - rubygems
ingestedAt: '2026-07-21T22:55:08.701Z'
---

## Overview

## Summary

Loofah's HTML5 sanitizer restricted only the `xlink:href` attribute on certain SVG elements to local, same-document references. Browsers also accept a plain `href` attribute as an alternative to the deprecated `xlink:href` per the SVG 2 spec, but Loofah did not apply the same restriction to it, allowing those elements to reference arbitrary external documents.

## Impact

SVG `<use>` can load and render external SVG content by reference. If the referenced external SVG is same-origin and contains scripts or other dangerous content, it could execute in the context of the sanitized document. `<feImage>` can load external images, which can be used for tracking. Modern browsers restrict cross-origin `<use>` fetches, which limits but does not eliminate the risk.

Applications that sanitize user-supplied SVG (directly, or as part of HTML) with Loofah's default allowlist are affected.

## Mitigation

Upgrade to Loofah >= 2.25.2.

## Credit

Found by the maintainer, Mike Dalessio, during a security audit.

## Affected packages

- `loofah < 2.25.2`

## Remediation

Upgrade to a patched release:

- `loofah 2.25.2`