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/{message_id} used the chat-history deletion helper in backend/open_webui/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

open-webui

CVSS v3.1 GITHUB

6.5 MEDIUMCVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H

EPSS

0.59% chance of exploitation in the next 30 days, 47th percentile

Published

2026-09-09

Updated

2026-09-10

Proof-of-concept exploits (1)

• advisories/GHSA-3cgp-3cqx-j8w2

Security advisories

• open-webui/open-webui/security/advisories/GHSA-3cgp-3cqx-j8w2
• open-webui/open-webui/pull/28035

References

• CVE Record
• NVD entry