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CVE-2026-56672— ComfyUI: Stored XSS via /userdata/{file} due to Missing Content-Type Sanitization

Quick assessment

Affected
Comfy-Org ComfyUI
Exploitation
Public or AI PoC available; prioritize validation
Recommended action
Check the vendor advisory and references for a fixed version. If immediate upgrade is impossible, restrict exposure and increase monitoring.

ComfyUI 是一个基于节点的扩散模型图形用户界面（GUI）、API 和后端服务。在版本 0.28.0 之前，端点 会提供用户可控的 HTML 和 SVG 文件，并根据文件扩展名派生内容类型（Content-Type）。这使得攻击者能够在 ComfyUI 的源上下文中实施存储型跨站脚本攻击（Stored XSS），进而窃取存储在浏览器中的 API 令牌、用户设置、工作流配置，并发起具有相同权限等效性的 API 请求。 该处理器使用了 来响应请求，因此上传的 或 文件会被服务器以 或 的内容类型进行提供。 端点允许

CVSS 8.2 · High EPSS 0.40% · P34

Affected Version Matrix 1

VendorProduct Version RangeStatus
Comfy-Org ComfyUI < 0.28.0 affected
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I. Basic Information for CVE-2026-56672

Vulnerability Information
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Vulnerability Title
ComfyUI: Stored XSS via /userdata/{file} due to Missing Content-Type Sanitization
Source: CVE Program / CVE List V5
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.
Source: CVE Program / CVE List V5
CVSS Information
CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:H/I:L/A:N
Source: CVE Program / CVE List V5
Vulnerability Type
在Web页面生成时对输入的转义处理不恰当(跨站脚本)
Source: CVE Program / CVE List V5

Affected Products

Vendor Product Affected Versions CPE Subscribe
Comfy-Org ComfyUI < 0.28.0 -

II. Public POCs for CVE-2026-56672

# POC Description Source Link Shenlong Link
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Qwen3.6-35B-A3B · 5569 chars
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III. Intelligence Information for CVE-2026-56672

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Vendor Advisories for CVE-2026-56672 (1)

Other References for CVE-2026-56672 (1)

Same Patch Batch · Comfy-Org · 2026-07-31 · 5 CVEs total

CVE-2026-68771 9.8 CRITICAL ComfyUI 0.23.0 Unauthenticated RCE via LoadTrainingDataset Pickle Deserialization
CVE-2026-56670 8.2 HIGH ComfyUI: Stored XSS via SVG file upload on the /view endpoint
CVE-2026-56673 7.5 HIGH ComfyUI: Path traversal in LoadImage via the /prompt API allows arbitrary file existence p
CVE-2026-56671 7.5 HIGH ComfyUI: Path traversal in /experiment/models/preview allows arbitrary image file read

IV. Related Vulnerabilities

Same product: ComfyUI
Same vendor: Comfy-Org
Same weakness: CWE-79