CVE-2026-73490 Loofah: SVG `href` attribute bypasses local-reference restriction
Attackers can bypass SVG sanitization restrictions to inject scripts or track users via external references in applications using Loofah.
- Exploited in the wild
- Not known
- Login needed
- Not needed
- Attackable
- Over the internet
- Victim action needed
- A user has to click or open something
- Fix
- Available
What is CVE-2026-73490?
CVE-2026-73490 is a medium-severity cross-site scripting vulnerability in flavorjones loofah, published on 12 Aug 2026. An attacker can exploit it over the internet without logging in, and only if a user opens a file or follows a link.
Official description
Loofah is a general library for manipulating and transforming HTML/XML documents and fragments, built on top of Nokogiri. Prior to 2.25.2, Loofah's HTML5 sanitizer applies its local-reference restriction only to the xlink:href attribute on SVG use and feImage elements, while browsers also accept the plain href attribute. A crafted sanitized SVG can therefore reference an arbitrary same-origin external document; use may render external SVG content containing scripts or other dangerous content, and feImage may load external images for tracking. Applications that sanitize user-supplied SVG with Loofah's default allowlist are affected. This issue is fixed in version 2.25.2.
Weakness: CWE-79
Which versions are affected by CVE-2026-73490?
2 open source packages ship an affected version, including loofah.
| Package | Affected | Fixed in |
|---|---|---|
loofah RubyGems | All versions | 2.25.2 |
loofah RubyGems | All versions | 2.25.2 |
How do I fix CVE-2026-73490?
Upgrade loofah to 2.25.2 or later.
Escape output for the context it lands in and set a strict Content Security Policy. Upgrading the affected component is the real fix. More about Cross-site scripting.
Is CVE-2026-73490 being exploited?
There is no known exploitation of CVE-2026-73490 in the wild and no public exploit code.
Sources
Also known as DEBIAN-CVE-2026-73490, GHSA-9wjq-cp2p-hrgf, UBUNTU-CVE-2026-73490.