svg-sanitizer is a PHP SVG/XML sanitizer. Prior to 1.0.0, Resolver::processReferences() in src/ElementReference/Resolver.php builds the SVG <use> reference graph with a case-sensitive href attribute predicate before cleanHrefAttributes() normalizes mixed-case names. An attacker can provide xlink:HrEf on nested <use> elements so the graph omits those references, after which the sanitizer converts the attribute to canonical xlink:href and returns the live nesting structure without applying the useNestingLimit protection.
A consuming application that renders the sanitized SVG can therefore be exposed to the resource exhaustion that control is designed to prevent. This issue is fixed in version 1.0.0.
Attack Parameters
Attack Vector
Network
Can be exploited remotely
Attack Complexity
Low
Easy to exploit
Privileges Required
None
No privileges needed
User Interaction
Required
User action required
Impact Assessment
Confidentiality
None
No data leak
Integrity
None
No data modification
Availability
High
Complete denial of service
CVSS Vector v3.1
Weakness Type (CWE)
References 3
https://github.com/darylldoyle/svg-sanitizer/commit/2dff6628314de8519155b7feb21…
security-advisories@github.com
https://github.com/darylldoyle/svg-sanitizer/releases/tag/1.0.0
security-advisories@github.com
https://github.com/darylldoyle/svg-sanitizer/security/advisories/GHSA-m9xh-6747…
security-advisories@github.com