Moleculer: Unauthenticated Denial of Service via negative length field in the TCP transporter packet parser
The TCP transporter's packet parser (src/transporters/tcp/parser.js) reads the packet length field with Buffer.prototype.readInt32BE, a signed read. A crafted packet whose length field has the sign bit set yields a negative length. The parser then advances past the parsed message with packet = packet.slice(length), but Buffer.prototype.slice clamps an out-of-range negative start index to 0, so the buffer is returned unchanged. The while (packet.length > 0) loop condition therefore never becomes false, …