Insufficient Session Expiration

Summary

authentik is an open-source Identity Provider. Prior to versions 2025.8.5 and 2025.10.0-rc1 prior to 2025.10.2, in previous authentik versions, invitations were considered valid regardless if they are expired or not, thus relying on background tasks to clean up expired ones. In a normal scenario this can take up to 5 minutes because the cleanup of expired objects is scheduled to run every 5 minutes. However, with a large amount of tasks in the backlog, this might take longer. A workaround involves creating a policy that explicitly checks whether the invitation is still valid, and then bind it to the invitation stage on the invitation flow, and denying access if the invitation is not valid.