The Okta Access Gateway includes an optional pass-through authentication source that accepts user identity from a client-supplied HTTP header without cryptographic validation. In architectures where this optional source is enabled without an upstream reverse proxy or firewall configured to sanitize and enforce client headers, an unauthenticated user can supply an arbitrary identity value to initiate a session.
Upgrade the Okta Access Gateway appliance to version 2026.9.1 or greater.