CVE-2026-106443: WeasyPrint: EPS images reach the Ghostscript interpreter resulting in RCE

This was found during a pentest, funded by the NLNnet foundation, conducted by Stefan Vink from Radically Open Security and the only High issue found.

WeasyPrint passes fetched image bytes directly to Pillow’s generic format dispatcher without restricting the input format. When Ghostscript is installed on the host, Pillow’s EpsImagePlugin invokes it to rasterize attacker-controlled EPS/PS input. Any content that can supply an image to WeasyPrint (an URL, CSS image value, SVG image reference, or data URI) can therefore drive untrusted PostScript into an external interpreter. On hosts running a Ghostscript version with a known -dSAFER bypass, this yields remote code execution.