hacnho/messagepack-msgspec-map32-int-nil-materialization-dos-poc

MessagePack msgspec map32 int->nil materialization DoS PoC

This repository contains a benign security research PoC for a .msgpack artifact that drives large map materialization during normal msgspec.msgpack.decode(...) parsing.

Files:

• control_bin32_same_size.msgpack
• malicious_map32_int_nil_2000000.msgpack
• reproduce.py

Observed behavior:

• control artifact:
  • parses successfully as bytes
• malicious artifact:
  • same size as control
  • parses successfully as a dict
  • materializes 2,000,000 entries
  • materially increases peak RSS during normal parse

Public files:

• https://huggingface.co/hacnho/messagepack-msgspec-map32-int-nil-materialization-dos-poc/resolve/main/control_bin32_same_size.msgpack
• https://huggingface.co/hacnho/messagepack-msgspec-map32-int-nil-materialization-dos-poc/resolve/main/malicious_map32_int_nil_2000000.msgpack
• https://huggingface.co/hacnho/messagepack-msgspec-map32-int-nil-materialization-dos-poc/resolve/main/reproduce.py

Reproduction:

python3 build_poc.py
python3 reproduce.py