CVE-2026-88002 Open WebUI: Any authenticated user can hang the server via a cyclic chat message history
An authenticated user can cause a denial of service in Open WebUI by creating cyclic chat messages that hang the server.
- Exploited in the wild
- Not known
- Login needed
- Any signed-in user
- Attackable
- Over the internet
- Victim action needed
- Not needed
- Fix
- Available
What is CVE-2026-88002?
CVE-2026-88002 is a medium-severity denial of service vulnerability in Openwebui Open Webui, published on 9 Sep 2026. Any signed-in user can exploit it over the network, with no action from the victim.
Official description
Open WebUI is an extensible, feature-rich, and user-friendly self-hosted AI platform. From 0.5.0 until 0.11.1, the message-chain reconstruction helper in backend/open_webui/utils/misc.py advanced through a chat history by map key but tracked visited entries using each message body's optional id field. An authenticated user could store id-less messages in a parent cycle and trigger a non-terminating walk that blocked the async event loop, grew memory until termination, and remained persistent across process restarts. This issue is fixed in version 0.11.1.
Weakness: CWE-835
Which versions are affected by CVE-2026-88002?
3 open source packages ship an affected version, including open-webui. It affects 1 product.
| Package | Affected | Fixed in |
|---|---|---|
open-webui PyPI | From 0.5.0 | 0.11.1 |
open-webui PyPI | From 0.5.0 | 0.11.1 |
open-webui PyPI | From 0.5.0 | 0.11.1 |
Products include Openwebui Open Webui.
How do I fix CVE-2026-88002?
Upgrade open-webui to 0.11.1 or later.
Upgrade, then put limits on request size, rate and nesting depth so one client cannot exhaust the service. More about Denial of service.
Is CVE-2026-88002 being exploited?
There is no known exploitation of CVE-2026-88002 in the wild and no public exploit code.
Other vulnerabilities in Openwebui Open Webui
- CVE-2026-44551 Open WebUI: LDAP Empty Password Authentication Bypass
- CVE-2026-56400 open-webui - Remote Code Execution via CORS Misconfiguration and Session Validation
- CVE-2024-8017 Cross-site Scripting (XSS) in open-webui/open-webui
- CVE-2026-45672 Open WebUI: Jupyter code execution works despite `ENABLE_CODE_EXECUTION=false` — feature gate bypassed
- CVE-2026-87995 Open WebUI: Same-origin XSS to account takeover via terminal port-preview iframe hardcoding allow-same-origin
Sources
Also known as GHSA-jqhh-cjmq-vmv6, PYSEC-2026-3879.