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CVE-2026-56672

ComfyUI: Stored XSS via /userdata/{file} due to Missing Content-Type Sanitization PUBLISHED

Description (CNA)

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 (CNA)

Vendor / productVersions
Comfy-Org / ComfyUIaffected < 0.28.0

CWE

CWE-79

References

ADP enrichment

CISA-ADP

No English description supplied.

No references supplied.