# CVE-2026-56672: Comfy-Org ComfyUI stored XSS in userdata endpoint

Source: https://junglewise.ai/threats/cve-2026-56672-comfy-org-comfyui-stored-xss-in-userdata-endpoint  
Publisher: Junglewise Threat Intelligence, https://junglewise.ai/threats  
Published: 2026-07-31. Updated: 2026-07-31  
License: CC BY 4.0 with a link back

CVE-2026-56672 · Severity: high · CVSS 8.2 · Published 2026-07-31

ComfyUI, a popular interface for AI diffusion models, was found to be vulnerable to a security flaw that could allow attackers to steal sensitive information. By tricking a user into clicking a malicious link, an attacker could execute scripts in the user's browser to access API tokens, private workflows, and account settings. This could lead to unauthorized access to the user's AI generation environment and data.

Technologies: [Comfy-Org ComfyUI](https://junglewise.ai/threats/technologies/comfyui). Vendors: [Comfy-Org](https://junglewise.ai/threats/vendors/comfy-org).

## Quick answers

**Is CVE-2026-56672 exploited in the wild?** No. Junglewise Threat Intelligence has no report of CVE-2026-56672 being exploited in the wild.

**How severe is CVE-2026-56672?** High severity, with a CVSS score of 8.2, published 31 July 2026.

**Which products and versions are affected?** Comfy-Org ComfyUI < 0.28.0.

**Is there a fix for CVE-2026-56672?** A patch was published on 2026-07-02: Fix committed to repository Junglewise finds every place you run it, drafts the upgrade and applies it once you approve.

**How is CVE-2026-56672 attacked?** It is attacked over the network, in a network appliance.

**Am I affected by CVE-2026-56672?** Check whether you run Comfy-Org ComfyUI at an affected version. Junglewise does that check for you around the clock: connect your code, cloud and domains, and it matches new vulnerabilities like this one against what you actually run and tells you when one reaches you.

## Technical details

A stored cross-site scripting (XSS) vulnerability exists in ComfyUI prior to version 0.28.0. The 'GET /userdata/{file}' endpoint served user-uploaded files using extension-derived Content-Types without proper sanitization or download enforcement. An attacker can use 'POST /userdata' to upload malicious HTML or SVG files containing scripts. When a victim navigates to the file's URL, the script executes within the ComfyUI origin, providing access to browser-stored API tokens (auth_token_comfy_org), settings, and workflows. The fix in version 0.28.0 forces dangerous MIME types to 'application/octet-stream' and implements 'Content-Disposition: attachment' and 'X-Content-Type-Options: nosniff'.

## Affected products

- Comfy-Org ComfyUI < 0.28.0

## Timeline

- 2026-07-02: patched: Fix committed to repository
- 2026-07-15: advisory: GitHub Security Advisory published
- 2026-07-31: disclosed: CVE published to NVD

## References

- [https://github.com/Comfy-Org/ComfyUI/commit/96e0e3585b41e1417442eaa14ec57f7b4ffcb5e0](https://github.com/Comfy-Org/ComfyUI/commit/96e0e3585b41e1417442eaa14ec57f7b4ffcb5e0)
- [https://github.com/Comfy-Org/ComfyUI/releases/tag/v0.28.0](https://github.com/Comfy-Org/ComfyUI/releases/tag/v0.28.0)
- [https://github.com/Comfy-Org/ComfyUI/security/advisories/GHSA-53g8-45wq-pcv8](https://github.com/Comfy-Org/ComfyUI/security/advisories/GHSA-53g8-45wq-pcv8)

## Related threats

- [ComfyUI path traversal in dataset save nodes](https://junglewise.ai/threats/cve-2026-92816-comfyui-path-traversal-in-dataset-save-nodes)
- [Comfy-Org ComfyUI unsafe deserialization in LoadTrainingDataset node](https://junglewise.ai/threats/cve-2026-68771-comfy-org-comfyui-unsafe-deserialization-in-loadtrainingdataset)
- [ComfyUI path traversal in LoadImage and media nodes](https://junglewise.ai/threats/cve-2026-56673-comfyui-path-traversal-in-loadimage-and-media-nodes)
- [Comfy-Org ComfyUI path traversal in model preview endpoint](https://junglewise.ai/threats/cve-2026-56671-comfy-org-comfyui-path-traversal-in-model-preview-endpoint)
- [Comfy-Org ComfyUI stored XSS in /view endpoint via SVG upload](https://junglewise.ai/threats/cve-2026-56670-comfy-org-comfyui-stored-xss-in-view-endpoint-via-svg-upload)