Shai-Hulud Themed Malware Found in the PyTorch Lightning AI Training Library

The PyPI package 'lightning', a widely-used deep learning framework, was compromised in a supply chain attack affecting versions 2.6.2 and 2.6.3 published on April 30, 2026. Teams building image classifiers, fine-tuning LLMs, running diffusion models, or developing time-series forecasters frequently have lightning somewhere in their dependency tree. Running pip install lightning is all that is needed to activate. The malicious versions contain a hidden _runtime directory with obfuscated JavaScript payload that executes automatically upon module import. The attack steals credentials, authentication tokens, environment variables, and cloud secrets, while also attempting to poison GitHub repositories.

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