In yet another software supply chain attack, threat actors have managed to compromise the popular Python package Lightning to push two malicious versions to conduct credential theft. According to Aikido Security, OX Security, Socket, and StepSecurity, the two malicious versions are versions 2.6.2 and 2.6.3, both of which were published on April 30, 2026. The campaign is assessed to be an extension of the Mini Shai-Hulud supply chain incident that targeted SAP-related npm packages on Wednesday. As of writing, the project has been quarantined by the administrators of the Python Package Index (PyPI) repository. PyTorch Lightning is an open-source Python framework that provides a high-level interface for PyTorch. The open-source project has more than 31,100 stars on GitHub. "The malicious package includes a hidden _runtime directory containing a downloader and an obfuscated JavaScript payload," Socket said. "The execution chain runs automatically when the lightning module is imported, requiring no additional user action after installation and import." The attack chain paves the way for a Python script ("start.py"), which downloads and executes the Bun JavaScript runtime, and then uses it to run an 11MB obfuscated malicious payload ("router_runtime.js") with an aimto conduct comprehensive credential theft. From among the harvested credentials, the GitHub tokens are validated against the "api.github[.]com/user" endpoint before being used to inject a worm-like payload to up to 50 branches retrieved from every repository the token can write to. "The operation is an upsert: it creates files that do not yet exist and silently overwrites files that do," Socket added. "No pre-check for existing content is performed. Every poisoned commit is authored using a hardcoded identity designed to impersonate Anthropic's Claude Code." Separately, the malware implements an npm-based propagation vector that modifies the developer's local npm packages with a postinstall hook in the "