CVE-2026-84691: Automation-controller: automation-controller-container: automation-controller: format string injection in the api 4xx error log setting discloses django secret_key and database credentials to an administrator

A flaw was found in Red Hat Ansible Automation Platform's automation- controller. The setting that formats the log message emitted for API 4XX errors is an administrator-controlled Python format-string template that is rendered with a live user object as an argument. Because Python string formatting permits attribute and item traversal on its arguments, an administrator can craft a template that walks from the user object into the application settings and reads the Django secret key and the database password. The formatted message is written to a logger that can be forwarded to an external log aggregator, whose destination is also administrator-controlled, allowing the secrets to be sent off the host. An authenticated administrator can thereby obtain the master encryption key used to protect all stored credentials and the database service password, enabling offline decryption of every stored credential, forgery of user sessions, and direct access to the controller database.