Python package security in 2026: How supply chain attacks are targeting your AI development environment
Brief
On March 24, 2026, developers building AI applications with LiteLLM — a Python package with 95 million monthly downloads — unknowingly installed malicious code. A threat actor group known as TeamPCP had compromised the PyPI distribution pipeline and pushed malicious versions 1.
- 7 and 1.
- 8 to the package index. The payload was subtle: a .
pth file, a little-known Python mechanism that auto-executes code every time the interpreter starts. If you installed either compromised version, malicious code ran silently — no explicit import needed.
That is not the exception anymore. It is the pattern.
What is actually happening
ReversingLabs reports that malicious open-source packages rose by 73% in 2026.