GitHub is turning a quiet trust leak into a visible failure. The problem is not the checkout step itself. It is privileged automation that runs code from a forked pull request with the base repository’s token, secrets, cache access, and runner environment.
GitHub Actions checkout v7 now blocks common pwn-request patterns by default in pull_request_target and certain workflow_run events. GitHub said the protection is live now in v7 and will be backported to supported major versions on July 16, 2026, so workflows pinned to floating major tags should pick it up automatically.
The breakage is deliberate. Privileged PR jobs that used to succeed may now fail because they were implicitly trusting unreviewed fork code, and that failure exposes secret-exposure patterns maintainers may not have noticed.