Attack Chain

1. An attacker compromises a legitimate user's JSON Web Token (JWT) for Open WebUI.
2. The legitimate user signs out from Open WebUI, or their Identity Provider initiates an OIDC back-channel logout.
3. Open WebUI's Redis instance correctly records the compromised JWT as revoked and updates the user's revoked_at timestamp.
4. The attacker attempts to use the revoked JWT to access Open WebUI's HTTP REST API endpoints; these attempts are correctly denied with a 401 Unauthorized error due to proper revocation checks.
5. The attacker then initiates a new connection to one of Open WebUI's realtime endpoints, such as a Socket.IO connection (for chat, collaborative notes) or a terminal websocket.
6. The attacker presents the previously revoked JWT to the realtime endpoint for authentication.
7. Due to CVE-2026-59219, the realtime endpoint's authentication logic only performs checks for token signature validity and expiry, but critically fails to consult the Redis revocation status.
8. The attacker successfully authenticates to the realtime service, gaining unauthorized access to and control over features like reading channel messages, participating in collaborative notes, and accessing terminal sessions as the legitimate user, despite the token having been officially revoked.

Impact

The successful exploitation of CVE-2026-59219 allows an attacker to maintain unauthorized, persistent access to an Open WebUI user's realtime functionalities, even after the legitimate user has performed a sign-out or an OIDC back-channel logout has been processed. This bypasses the intended remediation for compromised tokens. Attackers can leverage this persistent access to join user, channel, and note rooms, receive realtime channel messages and collaborative note updates, drive socket-level collaboration, and pass authentication for terminal websockets. This can lead to sensitive information disclosure, unauthorized data manipulation in collaborative environments, and potential remote execution capabilities if terminal servers are configured, effectively allowing the attacker to impersonate the victim in realtime interactions.

Recommendation

• Patch CVE-2026-59219 immediately by upgrading all affected Open WebUI installations to version 0.10.0 or later.
• Ensure that Open WebUI instances configured with Redis are updated, as the vulnerability only manifests in this configuration.
• Review network logs for suspicious long-lived connections to Open WebUI's Socket.IO or websocket endpoints from IP addresses not associated with legitimate users, which could indicate a post-revocation bypass attempt.