ComfyUI versions before 0.28.0 have a CWE-22 path traversal vulnerability in the get_model_preview function located in app/model_manager.py. The function constructs file paths by joining a user-controlled filename parameter to a model directory path without validating that the resulting path remains within the intended directory. Attackers can exploit this by supplying traversal sequences (../), percent-encoded traversal (%2e%2e%2f), or absolute paths, as well as unbounded path_index values, to access arbitrary image-decodable files on the host system. The files are then processed by the Pillow library and re-encoded as WEBP images, which limits the impact to disclosure of image-compatible files and allows enumeration of file existence through error messages. This vulnerability is addressed in ComfyUI version 0.28.0.

An unauthenticated remote attacker can read arbitrary image-decodable files on the host system running ComfyUI versions prior to 0.28.0. This can lead to sensitive information disclosure limited to files processable by the Pillow library. Additionally, the vulnerability allows file existence enumeration and internal path leakage via errors triggered by unbounded path_index values. There is no indication of integrity or availability impact.

This vulnerability is fixed in ComfyUI version 0.28.0. Users should upgrade to version 0.28.0 or later to remediate this issue. No official patch or temporary fix is indicated beyond upgrading. Since this is not a cloud service, remediation is the responsibility of the user.