{"id":"CVE-2026-29186","aliases":[],"url":"https://o3.security/vulnerability/CVE-2026-29186","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 < 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)","published":"2026-03-05T00:12:07Z","modified":"2026-03-09T16:02:26.288095Z","cvss":{"score":7.7,"severity":"HIGH","vector":"CVSS:3.1/AV:N/AC:H/PR:L/UI:N/S:C/C:H/I:L/A:L"},"epss":null,"cisaKev":null,"exploitsKnown":0,"affectedPackages":[{"ecosystem":"npm","name":"@backstage/plugin-techdocs-node","fixedVersion":"1.14.3"}],"fix":null,"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"}],"provenance":{"sources":["OSV.dev","FIRST.org (EPSS)"],"lastVerified":"2026-03-09T16:02:26.288095Z"}}