REDHAT-BUG-2536500: High severity RabbitMQ rabbitmq-c vulnerability

rabbitmq-c is a C-language AMQP client library for RabbitMQ. Prior to 0.16.0, a malicious AMQP server can send an undersized connection.tune.framemax value during amqplogin(), and rabbitmq-c accepts the value in amqplogininner() in librabbitmq/amqpsocket.c. amqptuneconnection() in librabbitmq/amqpconnection.c uses framemax to reallocate the outbound buffer without enforcing AMQPFRAMEMINSIZE. Immediate serialization of connection.tune-ok through amqpframetobytes() writes beyond the undersized heap allocation, causing memory corruption and likely denial of service. An on-path attacker can also trigger the flaw against plaintext AMQP traffic. Code execution is theoretically possible but was not demonstrated. This issue is fixed in version 0.16.0.