CVE-2026-67418 RabbitMQ MQTT 5: inapplicable PUBLISH property disconnects matching subscribers

RabbitMQ is a messaging and streaming broker. From 3.13.0 until 3.13.19, 4.0.24, 4.1.15, 4.2.10, and 4.3.5, the MQTT 5 parser in deps/rabbitmqmqtt/src/rabbitmqttpacket.erl accepts Request-Problem-Information on PUBLISH packets even though the property is valid only for CONNECT. An authenticated...