CVE-2026-54010: Open WebUI: Forged chat-file link allows cross-user file read and deletion

Open WebUI v0.9.5 lets an authenticated user attach arbitrary file_id values to their own chat message without checking whether they own or can read those files. If the attacker then shares that chat and grants themselves read access, has_access_to_file() treats the victim file as accessible through the shared chat, and the file endpoints read or delete the victim file.