{"id":"CVE-2021-21423","aliases":["GHSA-gg2g-m5wc-vccq","PYSEC-2021-111"],"url":"https://o3.security/vulnerability/CVE-2021-21423","summary":"Rebuild-bot workflow may allow unauthorised repository modifications","details":"`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 contrast with workflows triggered by `pull_request` events, which always execute with a `GITHUB_TOKEN` belonging to the repository from which the pull-request is made). Repositories that do not have branch protection configured on their default branch (typically `main` or `master`) could possibly allow an untrusted user to gain access to secrets configured on the repository (such as NPM tokens, etc). Branch protection prohibits this escalation, as the managed `GITHUB_TOKEN` would not be able to modify the contents of a protected branch and affected workflows must be defined on the default branch.","published":"2021-04-06T19:15:14.787Z","modified":"2026-07-09T12:20:08.683795Z","cvss":{"score":8.1,"severity":"HIGH","vector":"CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:N"},"epss":null,"cisaKev":null,"exploitsKnown":0,"affectedPackages":[{"ecosystem":"npm","name":"projen","fixedVersion":"0.16.41"},{"ecosystem":"PyPI","name":"projen","fixedVersion":"0.16.41"}],"fix":{"url":"https://github.com/projen/projen/commit/36030c6a4b1acd0054673322612e7c70e9446643","label":"projen/projen@36030c6"},"references":[{"type":"ADVISORY","url":"https://github.com/projen/projen/security/advisories/GHSA-gg2g-m5wc-vccq"},{"type":"ADVISORY","url":"https://www.npmjs.com/package/projen"},{"type":"FIX","url":"https://github.com/projen/projen/commit/36030c6a4b1acd0054673322612e7c70e9446643"}],"provenance":{"sources":["OSV.dev","FIRST.org (EPSS)"],"lastVerified":"2026-07-09T12:20:08.683795Z"}}