Simon Willison’s Weblog

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29th March 2026

Tool Python Vulnerability Lookup — Search Python packages for known security vulnerabilities by pasting a `pyproject.toml` or `requirements.txt` file, or by loading dependencies directly from a GitHub repository. The tool queries the OSV.dev vulnerability database and displays detailed information about any identified vulnerabilities, including severity levels, affected version ranges, and links to full disclosure reports.

I learned that the OSV.dev open source vulnerability database has an open CORS JSON API so I had Claude Code build this HTML tool for pasting in a pyproject.toml or requirements.txt file (or name of a GitHub repo containing those) and seeing a list of all reported vulnerabilities from that API.

This is a beat by Simon Willison, posted on 29th March 2026.

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