// CanvasHIGH
Discourse (Canvas) patched a critical image upload vulnerability chain affecting file disclosure. The flaw combined JPEG processing delays, Ghostscript execution, and ImageMagick SVG parsing to read arbitrary server files from any Trust Level 0 account. A separate cache poisoning vulnerability allowed JavaScript execution to anonymous visitors. Both issues were patched in June 2026 before disclosure; CVE-2026-55420 covers the image pipeline flaw affecting default configurations.
// Get alerts for Canvas