CVE-2026-70483

Name of the Vulnerable Software and Affected Versions Open WebUI versions 0.9.6 through 0.10.2

Description An issue exists where the DELETE /api/v1/chats/{id} endpoint cancels in-flight tasks before verifying if the caller has the necessary permissions to delete the chat. An authenticated user who possesses another user's chat ID can abort that user's active model responses, title generation, or tag generation. While the system ultimately refuses the deletion request and no data is deleted, modified, or disclosed, this allows an attacker to repeatedly interrupt another user's generations. The root cause is located in the delete chat by id function within backend/open webui/routers/chats.py, where the cancellation logic was executed before ownership and permission checks.

Recommendations Update Open WebUI to version 0.11.0. As a temporary mitigation, restrict access to the DELETE /api/v1/chats/{id} endpoint to only authorized administrators.