README.md

CNTK v2 Integer Overflow PoC

Proof-of-Concept demonstrating multiple integer overflow vulnerabilities in Microsoft CNTK v2 (Cognitive Toolkit) model loading.

Vulnerabilities

1. NDShape::TotalSize() Unsigned Integer Overflow → Heap Buffer Overflow
2. Signed Integer Overflow in ConvolveGeometry → Undefined Behavior
3. ONNX Import Path → Same TotalSize() Overflow

Files

• cntk-poc.cpp — Standalone PoC demonstrating all three overflow vectors

Build & Run

clang++ -std=c++17 -fsanitize=undefined,address -O1 -o poc cntk-poc.cpp
./poc

Target

• Repository: https://github.com/microsoft/CNTK
• Format: CNTK v2 .model (protobuf-based)
• CVSS: 7.8 (High) — AV:L/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H