A flaw in the role‑synchronization logic of Open WebUI caused an administrator’s database role to be updated while an existing Socket.IO connection remained cached and active. The bug stemmed from a recent change in the backend that failed to invalidate the cached user record, allowing a demoted administrator to keep an open connection and access every user’s collaborative notes. As a result, the attacker could read and edit notes without any additional privileges, violating confidentiality and integrity protections within the application.

The vulnerability affects Open WebUI versions from 0.9.0 through 0.11.1. The fix is included in release 0.11.1 and later. All deployments of the vulnerable range of releases are impacted.

The CVSS score of 6.5 reflects a moderate severity privilege‑escalation scenario. EPSS is not available, and the vulnerability is not listed in the CISA KEV catalog, indicating no known widespread exploitation yet. Attackers likely need the ability to inject a trusted role header or manipulate an OAuth role mapping so the server re‑classifies an administrator as a lower‑privileged role. Once an administrator’s role is downgraded, the cached Socket.IO session grants them continued read/write access to all collaborative notes until that connection disconnects.