---
tags:
  - security
  - proof-of-concept
  - protobuf
license: mit
---

# Protocol Buffers GeneratedCodeInfo.Annotation path materialization DoS PoC

This repository contains a benign security research PoC for a `.pb` artifact
that drives repeated-scalar materialization during
`descriptor_pb2.GeneratedCodeInfo.Annotation.ParseFromString(...)`.

Files:

- `control_one_source_file.pb`
- `malicious_path_5000000.pb`
- `reproduce.py`

Observed behavior:

- control artifact:
  - parses successfully with one `source_file`
- malicious artifact:
  - parses successfully with `5,000,000` `path` integers
  - materially increases peak RSS during normal parse

Tested runtime:

```bash
python3 -m pip install protobuf==7.35.1
```

Public reproduction:

```bash
curl -L -O https://huggingface.co/hacnho/protobuf-generatedcodeinfo-annotation-path-dos-poc/resolve/main/control_one_source_file.pb
curl -L -O https://huggingface.co/hacnho/protobuf-generatedcodeinfo-annotation-path-dos-poc/resolve/main/malicious_path_5000000.pb
curl -L -O https://huggingface.co/hacnho/protobuf-generatedcodeinfo-annotation-path-dos-poc/resolve/main/reproduce.py
python3 reproduce.py --control control_one_source_file.pb --malicious malicious_path_5000000.pb
```