Infinite loop in Open WebUI - #VU146338
Published: August 31, 2026
Vulnerability identifier: #VU146338
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 a loop with an unreachable exit condition in the message-chain reconstruction helper in backend/open_webui/utils/misc.py when processing a crafted cyclic chat message history. A remote user can store a specially crafted chat history and trigger chat history reconstruction to cause a denial of service.
The issue is triggered by messages that reference each other through parent links while omitting the id field, 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