GHSA-8f34-f56x-9xph: msgpack5: Truncated map32 headers throw an unexpected error

A truncated map32 header causes an out-of-bounds buffer read and throws RangeError instead of IncompleteBufferError. Applications that rely on IncompleteBufferError to wait for additional bytes may terminate a request, stream, or worker unexpectedly. No adjacent memory is disclosed because the buffer implementation checks bounds. ### Patches The decoder now validates the complete five-byte map32 header before reading its length and reports truncated input as IncompleteBufferError. …