@grpc/grps-js implements the core functionality of gRPC purely in JavaScript, without a C++ addon. Prior to versions 1.10.9, 1.9.15, and 1.8.22, there are two separate code paths in which memory can be allocated per message in excess of the grpc.max_receive_message_length channel option: If an incoming message has a size on the wire greater than the configured limit, the entire message is buffered before it is discarded; and/or if an incoming message has a size within the limit on the wire but decompresses to a size greater than the limit, the entire message is decompressed into memory, and on the server is not discarded. This has been patched in versions 1.10.9, 1.9.15, and 1.8.22.
The product allocates memory based on an untrusted, large size value, but it does not ensure that the size is within expected limits, allowing arbitrary amounts of memory to be allocated.