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.
Attack Parameters
Attack Vector
Network
Can be exploited remotely
Attack Complexity
High
Difficult to exploit
Privileges Required
None
No privileges needed
User Interaction
Required
User action required
Impact Assessment
Confidentiality
Low
Partial data leak
Integrity
Low
Partial data modification
Availability
None
No disruption
CVSS Vector v3.1
Weakness Type (CWE)
References 4
https://github.com/flavorjones/loofah/commit/20867b9be689521887364b74822c41ef83…
security-advisories@github.com
https://github.com/flavorjones/loofah/pull/308
security-advisories@github.com
https://github.com/flavorjones/loofah/releases/tag/v2.25.2
security-advisories@github.com
https://github.com/flavorjones/loofah/security/advisories/GHSA-9wjq-cp2p-hrgf
security-advisories@github.com