Vulnerability · Published Sep 9, 2026 · Assigned by GitHub_M

CVE-2026-88000Open WebUI: Any authenticated user can hang the server via message deletion in a cyclic chat tree

Medium 6.5

In plain English

A medium-severity infinite loop in open-webui from open-webui. Proof-of-concept exploit code is public. The chance it is exploited in the next 30 days is estimated at 0.6% (higher than 48% of all known vulnerabilities). Fixed versions are available - upgrade the affected package.

Severity (CVSS 3.1)6.5Medium

Exploit odds (30 days)0.6%top 51.5% of all CVEs

Exploited in the wildNo reportsCISA SSVC: poc

Attack toolingNoneno public tooling known

Official description

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 packages & fixed versions

Ecosystem	Package	Fixed in	Advisory
PyPI	open-webui	0.11.1	GHSA-3cgp-3cqx-j8w2
PyPI	open-webui	0.11.1	PYSEC-2026-3877

Affected products (as reported)

Vendor	Product	Versions
open-webui	open-webui	>= 0.10.0, < 0.11.1

Weakness: CWE-835 · Vector: CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H

References

https://github.com/open-webui/open-webui/security/advisories/GHSA-3cgp-3cqx-j8w2 x_refsource_CONFIRM
https://github.com/open-webui/open-webui/pull/28035 x_refsource_MISC
https://github.com/open-webui/open-webui/commit/b933292d63d12be3fd1416fe55519ddc7aa336bc x_refsource_MISC
https://github.com/open-webui/open-webui/releases/tag/v0.11.1 x_refsource_MISC