CVE-2026-54022: Open WebUI: Any authenticated user can read other users' private notes via Socket.IO

Severity: medium (CVSS 5.3 v3.1)
Exploited in the wild: not listed in CISA KEV
EPSS: 0.3% probability of exploitation in the next 30 days
Public exploit or detection template: yes
Published: 2026-06-23 · updated 2026-06-25
Weakness: CWE-706

Description

Open WebUI is a self-hosted artificial intelligence platform designed to operate entirely offline. Prior to 0.8.11, the ydoc:document:join Socket.IO handler checks note ownership only when the document_id starts with note: (colon). However, the YdocManager storage layer normalizes all document IDs by replacing colons with underscores (document_id.replace(":", "_")). An attacker can join a document room using note_<id> (underscore) instead of note:<id> (colon), bypassing the authorization check entirely while accessing the same underlying Yjs document. The server then returns the full document state, leaking the victim's private note contents. This vulnerability is fixed in 0.8.11.

Affected products

open-webui: before 0.8.11 — fixed in 0.8.11

How to fix

Upgrade to a fixed version: open-webui 0.8.11. Check the vendor advisory for mitigations.

References

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