Responsibly disclosed by @NSEcho.
HTTP API did not enforce an HTTP request body limit, making it vulnerable for DoS attacks with very large messages.
An authenticated user with sufficient credentials can publish a very large messages over the HTTP API and cause target node to be terminated by an "out-of-memory killer"-like mechanism.
A PoC was provided to Team RabbitMQ privately.
Denial of Service
3.11.243.12.7Exploitability
AV:NAC:LPR:HUI:NScope
S:UImpact
C:NI:NA:H4.9/CVSS:3.1/AV:N/AC:L/PR:H/UI:N/S:U/C:N/I:N/A:H