Pivotal RabbitMQ versions 3.7.x prior to 3.7.21 and 3.8.x prior to 3.8.1 and RabbitMQ for Pivotal Platform 1.16.x versions prior to 1.16.7 and 1.17.x versions prior to 1.17.4 contain a web management plugin that is vulnerable to a denial of service attack. The \X-Reason\ HTTP Header can be leveraged to insert a malicious Erlang format string that will expand and consume the heap resulting in the server crashing.