savg-sanitizer is a PHP SVG/XML sanitizer. Prior to 1.0.0, svg-sanitizer allows a crafted SVG DTD with a #FIXED attribute default to make cleanAttributesOnWhitelist() perform a double DOMElement::removeAttribute() call on the same attribute name in src/Sanitizer.php. The first removal deletes the explicit attribute, while the DTD default rematerializes the value before the href safety path performs the second removal, which can corrupt libxml state and terminate the PHP worker.
An attacker who can submit SVG content to a sanitization endpoint can repeatedly interrupt workers and degrade or exhaust application availability. 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
Low
Basic privileges needed
User Interaction
None
No user interaction needed
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/23877db7e76f1e1df5c3e65ab30…
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-v383-3rw5…
security-advisories@github.com