{"id":"GHSA-928r-fm4v-mvrw","summary":"TechDocs Mkdocs Configuration Key Enables Arbitrary Code Execution","details":"### Impact\nThis is a configuration bypass vulnerability that enables arbitrary code execution. The `@backstage/plugin-techdocs-node` package uses an allowlist to filter dangerous MkDocs configuration keys during the documentation build process. \n\nA gap in this allowlist allows attackers to craft an `mkdocs.yml` that causes arbitrary Python code execution, completely bypassing TechDocs' security controls.     \n\n### Patches\n\nPatched in `@backstage/plugin-techdocs-node` version 1.14.3\n\n### Workarounds\nIf users cannot upgrade immediately:\n\n1. Use Docker mode with restricted access: Configure TechDocs with `runIn: docker` instead of `runIn: local`. This provides container isolation, though it does not fully mitigate the risk.\n2. Restrict repository access: Limit who can modify `mkdocs.yml` files in repositories that TechDocs processes. Only allow trusted contributors.\n3. Manual review: Implement PR review requirements for changes to `mkdocs.yml` files to detect malicious hooks configurations before they are merged.\n4. Downgrade MkDocs: Use MkDocs \u003c 1.4.0 (e.g., 1.3.1) which does not support hooks. Note: This may limit access to newer MkDocs features.\n\nNote: Building documentation in CI/CD pipelines using `@techdocs/cli` does not mitigate this vulnerability, as the CLI uses the same vulnerable `@backstage/plugin-techdocs-node` package.\n\n### Resources\n[MkDocs Hooks Documentation](https://www.mkdocs.org/user-guide/configuration/#hooks)\n[MkDocs 1.4 Release Notes](https://www.mkdocs.org/about/release-notes/#version-14-2022-09-27)\n[TechDocs Architecture](https://backstage.io/docs/features/techdocs/architecture)","aliases":["CVE-2026-29186"],"modified":"2026-03-09T16:02:26.288095Z","published":"2026-03-05T00:12:07Z","database_specific":{"severity":"HIGH","github_reviewed":true,"github_reviewed_at":"2026-03-05T00:12:07Z","nvd_published_at":"2026-03-07T15:15:55Z","cwe_ids":["CWE-434","CWE-74"]},"references":[{"type":"WEB","url":"https://github.com/backstage/backstage/security/advisories/GHSA-928r-fm4v-mvrw"},{"type":"ADVISORY","url":"https://nvd.nist.gov/vuln/detail/CVE-2026-29186"},{"type":"WEB","url":"https://backstage.io/docs/features/techdocs/architecture"},{"type":"PACKAGE","url":"https://github.com/backstage/backstage"},{"type":"WEB","url":"https://www.mkdocs.org/about/release-notes/#version-14-2022-09-27"},{"type":"WEB","url":"https://www.mkdocs.org/user-guide/configuration/#hooks"}],"affected":[{"package":{"name":"@backstage/plugin-techdocs-node","ecosystem":"npm","purl":"pkg:npm/%40backstage/plugin-techdocs-node"},"ranges":[{"type":"SEMVER","events":[{"introduced":"0"},{"fixed":"1.14.3"}]}],"database_specific":{"source":"https://github.com/github/advisory-database/blob/main/advisories/github-reviewed/2026/03/GHSA-928r-fm4v-mvrw/GHSA-928r-fm4v-mvrw.json","last_known_affected_version_range":"\u003c= 1.14.2"}}],"schema_version":"1.9.0","severity":[{"type":"CVSS_V3","score":"CVSS:3.1/AV:N/AC:H/PR:L/UI:N/S:C/C:H/I:L/A:L"}]}