CVE-2026-56672: Comfy-Org Comfyui

High severity, CVSS 8.2. EPSS: 0.4% chance of exploitation in the next 30 days.

ComfyUI is a node-based diffusion model GUI, API, and backend. Prior to 0.28.0, GET /userdata/{file} served user-controlled HTML and SVG files with extension-derived content types, allowing stored cross-site scripting in the ComfyUI origin and access to browser-stored API tokens, settings, workflows, and authenticated-equivalent API calls. The handler used web.FileResponse(path), so an uploaded .html/.svg was served as text/html/image/svg+xml. POST /userdata stores arbitrary request bodies (confined to the user's userdata directory). When a victim navigated to the file URL, the embedded script executed same-origin. The /view endpoint already forced dangerous MIME types to download; that protection had never been applied to /userdata. This issue is fixed in version 0.28.0.

Affected products

• Comfy-Org Comfyui: before 0.28.0 (fixed in 0.28.0)

Published 2026-07-31. Last modified 2026-09-08.