CVE-2026-88000: Open WebUI: Any authenticated user can hang the server via message deletion in a cyclic chat tree
Open WebUI is an extensible, feature-rich, and user-friendly self-hosted AI platform. From 0.10.0 until 0.11.1, DELETE /api/v1/chats/{id}/messages/{messageid} used the chat-history deletion helper in backend/openwebui/models/chats.py to follow childrenIds without recording visited message identifiers. An authenticated user could store a cyclic chat tree and delete a message, causing a synchronous infinite loop on the server request loop that blocked every user's requests until the process was killed. This issue is fixed in version 0.11.1.
Affected Software
Remediation
Recommended actions to resolve this vulnerability, in priority order.
- Upgrade
Upgrade
open_webuito a version that resolves this vulnerability.Fixed in 0.11.1
Event History
Frequently Asked Questions
Who can exploit this issue?
Any authenticated Open WebUI user can exploit it. No additional privileges or user interaction are required.
Which deployments are affected?
Open WebUI versions from 0.10.0 up to, but not including, 0.11.1 are affected. Version 0.11.1 fixes the issue.
What conditions are required to trigger the denial of service?
The attacker must be able to store a cyclic chat tree and then send a DELETE request for a message in that chat. The vulnerable deletion logic follows child message identifiers without tracking previously visited messages.
What is the operational impact of successful exploitation?
The deletion request can enter a synchronous infinite loop that blocks requests for all users. Service remains unavailable until the affected process is killed.