Open WebUI versions 0.8.8 through 0.11.3 protect terminal access by validating user status only when the WebSocket connection is first established. Because this check is not repeated for subsequent messages, a user that has been deactivated remains able to send commands and read or write files on the terminal server through the same open socket. The flaw allows unauthorized execution, data disclosure, and data modification by thwarting intended session revocation.

The vulnerability affects the Open WebUI product from the open-webui vendor. All releases from 0.8.8 up to, but not including, 0.11.4 are impacted, as documented in the advisory. Users deploying any of these versions should verify their installed version and check for available updates.

The CVSS score of 5.3 indicates moderate severity. EPSS data is unavailable, and the issue is not listed in the CISA KEV catalog, suggesting no widespread exploitation has been reported yet. The attack vector is likely indirect, requiring an attacker to have prior access to a terminal WebSocket session and then to deactivating the session without revoking the active connection. If successful, a deactivated user can continue to issue commands, potentially compromising confidentiality and integrity of files on the terminal server.