Vulnerability Description
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.
CVSS Score
HIGH
Related Weaknesses (CWE)
References
- https://github.com/Comfy-Org/ComfyUI/commit/96e0e3585b41e1417442eaa14ec57f7b4ffc
- https://github.com/Comfy-Org/ComfyUI/releases/tag/v0.28.0
- https://github.com/Comfy-Org/ComfyUI/security/advisories/GHSA-53g8-45wq-pcv8
FAQ
What is CVE-2026-56672?
CVE-2026-56672 is a vulnerability with a CVSS score of 8.2 (HIGH). 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 cro...
How severe is CVE-2026-56672?
CVE-2026-56672 has been rated HIGH with a CVSS base score of 8.2/10. Review the CVSS metrics above for detailed severity breakdown.
Is there a patch for CVE-2026-56672?
Check the references section above for vendor advisories and patch information. Review vendor security bulletins for remediation guidance.