WPGraphQL provides a GraphQL API for WordPress sites. Prior to version 2.9.1, the wp-graphql/wp-graphql repository contains a GitHub Actions workflow (release.yml) vulnerable to OS command injection through direct use of ${{ github.event.pull_request.body }} inside a run: shell block. When a pull request from develop to master is merged, the PR body is injected verbatim into a shell command, allowing arbitrary command execution on the Actions runner. Version 2.9.1 contains a fix for the vulnerability.