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.frame max value during amqp login(), and rabbitmq-c accepts the value in amqp login inner() in librabbitmq/amqp socket.c. amqp tune connection() in librabbitmq/amqp connection.c uses frame max to reallocate the outbound buffer without enforcing AMQP FRAME MIN SIZE. Immediate serialization of connection.tune-ok through amqp frame to bytes() 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.