Protobuf (< 0.16.1)

An unauthenticated attacker can trigger a denial-of-service condition in services that decode untrusted protobuf messages using the `Protobuf.Decoder` (Hex package `protobuf`) versions between 0.8.0 and 0.16.1 by crafting deeply nested self-referential message types, leading to memory exhaustion and service crashes.