{"id":"CVE-2026-29186","aliases":["EUVD-2026-10146","GHSA-928r-fm4v-mvrw"],"status":"published","title":"@backstage/plugin-techdocs-node: TechDocs Mkdocs Configuration Key Enables Arbitrary Code Execution","description":"Backstage is an open framework for building developer portals. Prior to version 1.14.3, this 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. A gap in this allowlist allows attackers to craft an mkdocs.yml that causes arbitrary Python code execution, completely bypassing TechDocs' security controls. This issue has been patched in version 1.14.3.","severity":{"version":"3.1","score":7.7,"vector":"CVSS:3.1/AV:N/AC:H/PR:L/UI:N/S:C/C:H/I:L/A:L","level":"high","assessor":"cna","from":"cve"},"epss":{"day":"2026-11-10","score":0.0087,"percentile":0.59122,"model":"v2026.06.15"},"facts":{"in_kev":false,"known_exploited":false,"public_exploit":false,"fix_available":true},"cwes":["CWE-434","CWE-74","CWE-791"],"published":"2026-03-05T00:12:07Z","modified":"2026-07-15T02:19:24Z","fixes":[{"ecosystem":"npm","package":"@backstage/plugin-techdocs-node","fixed_in":["1.14.3"],"sources":["ghsa","osv"]}],"affected":[{"source":"ghsa","ecosystem":"npm","package":"@backstage/plugin-techdocs-node","ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"},{"last_affected":"1.14.2"},{"fixed":"1.14.3"}]}]},{"source":"osv","ecosystem":"npm","package":"@backstage/plugin-techdocs-node","ranges":[{"type":"SEMVER","events":[{"introduced":"0"},{"fixed":"1.14.3"}]}]}],"products":[{"vendor":"backstage","product":"backstage"},{"vendor":"linuxfoundation","product":"backstage_plugin-techdocs-node"},{"vendor":"red hat","product":"red hat developer hub 1.8"},{"vendor":"red hat","product":"red hat developer hub 1.9"},{"vendor":"red hat","product":"self-service automation portal 2"}],"references":[{"url":"https://github.com/backstage/backstage/security/advisories/GHSA-928r-fm4v-mvrw","tags":["x_refsource_CONFIRM","Vendor Advisory","web"]},{"url":"https://access.redhat.com/security/cve/CVE-2026-29186","tags":["vdb-entry","x_refsource_REDHAT"]},{"url":"https://bugzilla.redhat.com/show_bug.cgi?id=2445480","tags":["issue-tracking","x_refsource_REDHAT"]},{"url":"https://security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-29186.json","tags":["x_sadp-csaf-vex"]},{"url":"https://access.redhat.com/errata/RHSA-2026:9742","tags":["vendor-advisory","x_refsource_REDHAT"]},{"url":"https://access.redhat.com/errata/RHSA-2026:13826","tags":["vendor-advisory","x_refsource_REDHAT"]},{"url":"https://backstage.io/docs/features/techdocs/architecture","tags":["web"]},{"url":"https://www.mkdocs.org/about/release-notes/#version-14-2022-09-27","tags":["web"]},{"url":"https://www.mkdocs.org/user-guide/configuration/#hooks","tags":["web"]},{"url":"https://nvd.nist.gov/vuln/detail/CVE-2026-29186","tags":["advisory"]},{"url":"https://github.com/advisories/GHSA-928r-fm4v-mvrw"},{"url":"https://github.com/backstage/backstage","tags":["package"]}],"sources":{"cve":[{"id":"CVE-2026-29186","title":"@backstage/plugin-techdocs-node: TechDocs Mkdocs Configuration Key Enables Arbitrary Code Execution","description":"Backstage is an open framework for building developer portals. Prior to version 1.14.3, this 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. A gap in this allowlist allows attackers to craft an mkdocs.yml that causes arbitrary Python code execution, completely bypassing TechDocs' security controls. This issue has been patched in version 1.14.3.","status":"published","published":"2026-03-07T15:03:51.422Z","modified":"2026-07-15T01:10:31.895Z","cvss":[{"version":"3.1","score":7.7,"vector":"CVSS:3.1/AV:N/AC:H/PR:L/UI:N/S:C/C:H/I:L/A:L","level":"high","assessor":"cna"},{"version":"3.1","score":9.1,"vector":"CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:C/C:H/I:L/A:L","level":"critical","assessor":"adp"}],"cwes":["CWE-434","CWE-74","CWE-791"],"updated_at":"2026-11-02T14:19:56.284359Z"}],"euvd":[{"id":"EUVD-2026-10146","description":"Backstage is an open framework for building developer portals. Prior to version 1.14.3, this 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. A gap in this allowlist allows attackers to craft an mkdocs.yml that causes arbitrary Python code execution, completely bypassing TechDocs' security controls. This issue has been patched in version 1.14.3.","status":"published","published":"2026-03-07T15:03:51Z","modified":"2026-07-15T01:10:31Z","cvss":[{"version":"3.1","score":9.1,"vector":"CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:C/C:H/I:L/A:L","level":"critical"}],"updated_at":"2026-11-02T18:19:55.842782Z"}],"ghsa":[{"id":"GHSA-928r-fm4v-mvrw","title":"TechDocs Mkdocs Configuration Key Enables Arbitrary Code Execution","description":"### 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)","status":"published","published":"2026-03-05T00:12:07Z","modified":"2026-03-09T15:46:45Z","cvss":[{"version":"3.1","score":7.7,"vector":"CVSS:3.1/AV:N/AC:H/PR:L/UI:N/S:C/C:H/I:L/A:L","level":"high"}],"cwes":["CWE-74","CWE-434"],"updated_at":"2026-11-02T14:39:33.538417Z"}],"nvd":[{"id":"CVE-2026-29186","description":"Backstage is an open framework for building developer portals. Prior to version 1.14.3, this 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. A gap in this allowlist allows attackers to craft an mkdocs.yml that causes arbitrary Python code execution, completely bypassing TechDocs' security controls. This issue has been patched in version 1.14.3.","status":"published","published":"2026-03-07T15:15:55.4Z","modified":"2026-07-15T02:19:24.873Z","cvss":[{"version":"3.1","score":7.7,"vector":"CVSS:3.1/AV:N/AC:H/PR:L/UI:N/S:C/C:H/I:L/A:L","level":"high","assessor":"secondary"},{"version":"3.1","score":9.8,"vector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H","level":"critical","assessor":"primary"},{"version":"3.1","score":9.1,"vector":"CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:C/C:H/I:L/A:L","level":"critical","assessor":"secondary"}],"cwes":["CWE-74","CWE-434","CWE-791"],"updated_at":"2026-11-02T14:12:08.279852Z"}],"osv":[{"id":"GHSA-928r-fm4v-mvrw","title":"TechDocs Mkdocs Configuration Key Enables Arbitrary Code Execution","description":"### 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)","status":"published","published":"2026-03-05T00:12:07Z","modified":"2026-03-09T16:02:26.288095Z","cvss":[{"version":"3.1","score":7.7,"vector":"CVSS:3.1/AV:N/AC:H/PR:L/UI:N/S:C/C:H/I:L/A:L","level":"high"}],"cwes":["CWE-434","CWE-74"],"updated_at":"2026-11-02T15:46:43.123867Z"}]}}