Infinite loop in Open WebUI - #VU146340
Published: August 31, 2026
Vulnerability identifier: #VU146340
CSH Severity: Low
CVSS v4: 7.1 [CVSS:4.0/AV:N/AC:L/AT:N/PR:L/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N]
CVE-ID: N/A
CWE-ID: CWE-835
Exploitation vector: Remote access
Exploit availability:
No public exploit available
Vulnerability details
The vulnerability allows a remote user to cause a denial of service.
The vulnerability exists due to an infinite loop in the chat-history message deletion helper in backend/open_webui/models/chats.py when deleting a message from a chat history whose childrenIds links form a cycle. A remote user can store a crafted cyclic chat tree and delete a message to cause a denial of service.
The issue is triggered through DELETE /api/v1/chats/{id}/messages/{message_id}, and the blocking work continues even if the client disconnects.
Affected software
Open WebUI
Remediation
Install security update from vendor's website.
Open WebUI - update to 0.11.1