CVE-2021-21423

projen is a project generation tool that synthesizes project configuration files such as package.json, tsconfig.json, .gitignore, GitHub Workflows, eslint, jest, and more, from a well-typed definition written in JavaScript. Users of projen's NodeProject project type (including any project type derived from it) include a .github/workflows/rebuild-bot.yml workflow that may allow any GitHub user to trigger execution of un-trusted code in the context of the "main" repository (as opposed to that of a fork). In some situations, such untrusted code may potentially be able to commit to the "main" repository. The rebuild-bot workflow is triggered by comments including @projen rebuild on pull-request to trigger a re-build of the projen project, and updating the pull request with the updated files. This workflow is triggered by an issue_comment event, and thus always executes with a GITHUB_TOKEN belonging to the repository into which the pull-request is made (this is in cont