What’s Vulnerable › Vulnerabilities

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

• Severity: medium (CVSS 6.5 v3.1)
• Exploited in the wild: not listed in CISA KEV
• EPSS: 0.6% probability of exploitation in the next 30 days
• Public exploit or detection template: yes
• Published: 2026-09-09 · updated 2026-09-14
• Weakness: CWE-835

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 products

• open-webui: from 0.10.0 before 0.11.1 — fixed in 0.11.1

How to fix

Upgrade to a fixed version: open-webui 0.11.1. Check the vendor advisory for mitigations.

References

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

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