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.
https://pivotal.io/security/cve-2019-11287
https://lists.debian.org/debian-lts-announce/2021/07/msg00011.html