CVE-2026-59714 Open WebUI: Cross-channel message overwrite via chat completion API (single-model and multimodel message_ids)

Open WebUI is an extensible, feature-rich, and user-friendly self-hosted AI platform. From 0.9.5 before 0.10.0, any authenticated user can overwrite the content of a message in a channel they do not belong to including private and DM channels by sending a chat completion request with a...

CVE-2026-59714

CVE-2026-59714 describes a cross-channel message overwrite vulnerability in Open WebUI exposed by the chat-completions path. From v0.9.5 to before v0.10.0, an authenticated user could overwrite a message in a channel they do not belong to by using a channel: chat_id with a caller-supplied message...