CVE-2026-106122: RabbitMQ: Malformed UTF-8 in shortstr properties permanently disables RPC consumers

A single AMQP message with malformed UTF-8 in a shortstr property (for example correlation-id) can permanently disable a Java client RPC consumer.

The client decodes malformed bytes into U+FFFD replacement characters. Each of those re-encodes to 3 bytes, so a 255-byte property becomes 765 bytes (over the 255-byte shortstr limit). When the application echoes that value back, as the documented RPC pattern does, the encoder throws an unchecked IllegalArgumentException. That kills the consumer loop or tears down the channel.

The message is never acknowledged, so the broker requeues it and it disables the next consumer that picks it up. Recovery does not help; the service stays down until an operator manually purges the queue.

In short: the decoder produces values the encoder rejects, and any client permitted to use an RPC service can permanently destroy it for everyone.