# PoC: BINUNICODE8 Signed/Unsigned Length Confusion in JIT Unpickler

**Vulnerability:** `unpickler.cpp:344` reads BINUNICODE8 length as `int64_t` (signed) instead of `uint64_t`. The implicit conversion to `size_t` in `readBytes()` causes 32-bit truncation on ARM mobile (pickle desync → corruption) and DoS on 64-bit (excessive allocation).

## Files

- `poc_binunicode8_overflow.py` — Full PoC with code analysis, 64-bit DoS demo, 32-bit truncation test
- `test_truncation.cpp` — Standalone C++ 32-bit truncation demonstration

## Quick Start

```bash
pip install torch
python poc_binunicode8_overflow.py
```

## Expected Output

- Part 1: Code analysis showing int64_t vs uint64_t mismatch
- Part 2: 64-bit DoS (MemoryError, end of archive, max_size rejection)
- Part 3: 32-bit truncation table (C++ test)
- Part 4: Pickle stream desync analysis on 32-bit ARM