This post is part of my weekly newsletter - Top 5 in Frontend and AI . Subscribe so you can deep dives like this in your inbox If you have pull_request_target anywhere in your workflows, the TanStack compromise could happen to you. Here's exactly how it happened. On May 11, a new strain of Shai-Hulud worm published 84 malicious versions across 42 @tanstack/* packages by chaining three GitHub Actions vulnerabilities - pull_request_target Pwn (Own) Request, cache poisoning across the fork ↔ base trust boundary, and OIDC token extraction from runner memory. Thankfully, no maintainer was phished and no token was stolen off a laptop. What happened An attacker opened a PR from a throwaway fork of TanStack/router . Although the maintainers never got a chance to review the PR since it was immediately closed, the CI workflow was triggered.…