LM Studio before 0.4.22+1 contains a path traversal vulnerability in the model downloader's resolveDownloadRequest that allows attackers to write files outside the models directory using backslash-separated traversal filenames. Attackers can trick users into downloading a crafted model repository that plants a plugin manifest.json, install-state.json and mcp-bridge-config.json, running an attacker-supplied Python payload on every launch.