A flaw was found in aap-gateway, a component of Ansible Automation Platform's Event-Driven Ansible (EDA). An unauthenticated remote attacker can bypass mutual Transport Layer Security (mTLS) authentication for event streams. This is achieved by manipulating the event stream URL and forging the HTTP Subject header. The system also inadvertently discloses the expected certificate subject in error messages, which simplifies the attack. This vulnerability allows an attacker to inject arbitrary events into EDA, potentially triggering automated workflows.