Vector: Unauthenticated denial of service in the `logstash` source via unbounded memory allocation.

Vector is a high-performance observability data pipeline. From 0.15.0 until 0.57.0, the logstash source reads a 32-bit compressed-frame length from the network and uses it to size an in-memory buffer without an upper bound. An unauthenticated remote peer that can reach the default 0.0.0.0:5044 listener can send a minimal frame declaring a multi-gigabyte payload, causing an excessive allocation that can abort Vector or invoke the host OOM killer. Because the allocation follows the declared length rather than bytes transmitted, the attacker has low resource cost, and process termination can halt log ingestion for every tenant on a shared pipeline. This issue is fixed in version 0.57.0.