CVE-2023-50262 Information

Description

Dompdf is an HTML to PDF converter for PHP. When parsing SVG images Dompdf performs an initial validation to ensure that paths within the SVG are allowed. One of the validations is that the SVG document does not reference itself. However prior to version 2.0.4 a recursive chained using two or more SVG documents is not correctly validated. Depending on the system configuration and attack pattern this could exhaust the memory available to the executing process and/or to the server itself.

php-svg-lib when run in isolation does not support SVG references for image elements. However when used in combination with Dompdf php-svg-lib will process SVG images referenced by an image element. Dompdf currently includes validation to prevent self-referential image references but a chained reference is not checked. A malicious actor may thus trigger infinite recursion by chaining references between two or more SVG images.

When Dompdf parses a malicious payload it will crash due after exceeding the allowed execution time or memory usage. An attacker sending multiple request to a system can potentially cause resource exhaustion to the point that the system is unable to handle incoming request.

Version 2.0.4 contains a fix for this issue.

Reference

https://github.com/dompdf/dompdf/security/advisories/GHSA-3qx2-6f78-w2j2 https://github.com/dompdf/dompdf/commit/41cbac16f3cf56affa49f06e8dae66d0eac2b593 https://github.com/dompdf/dompdf/blob/v2.0.3/src/Image/Cache.php#L136-L153