What’s Vulnerable › Vulnerabilities

CVE-2026-88002: Open WebUI: Any authenticated user can hang the server via a cyclic chat message history

• 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 0.5.0 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.

Affected products

• open-webui: from 0.5.0 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/5c79ccc9e5c9efc2bc024d8f0b9757652ece929a
• https://github.com/open-webui/open-webui/pull/28034
• https://github.com/open-webui/open-webui/releases/tag/v0.11.1
• https://github.com/open-webui/open-webui/security/advisories/GHSA-jqhh-cjmq-vmv6

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