Apache Airflow's asynchronous connection test checked permissions when the test was queued — only create permission when the connection ID did not exist yet — but, when the test completed with "commit_on_success", wrote the tested connection under that ID. A user allowed to create but not edit connections could overwrite a connection someone else had created in the meantime. Only deployments that enable the non-default "[core] test_connection" setting are affected. Users are advised to upgrade to apache-airflow 3.4.0 or later.