{"id":"CVE-2026-106509","aliases":["GHSA-8w7q-29mw-gf5c"],"url":"https://o3.security/vulnerability/CVE-2026-106509","summary":"Backstage: Improper validation of MkDocs theme configuration in TechDocs","details":"### Impact\n\nWhen TechDocs is configured to build documentation locally or in a container, a user with write access to a registered repository can include configuration values in `mkdocs.yml` that cause arbitrary code execution during the documentation build process.\n\n### Patches\n\nPatched in `@backstage/plugin-techdocs-node` version `1.15.4`\n\n### Workarounds\n\n- Configure TechDocs with `techdocs.generator.runIn: 'docker'` instead of `'local'` to provide container isolation, though this does not fully mitigate the risk.\n- Restrict write access to repositories registered in the Backstage catalog to trusted users.","published":"2026-10-06T21:50:07.721Z","modified":"2026-10-09T02:30:49.320602053Z","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":null,"affectedPackages":[{"ecosystem":"npm","name":"@backstage/plugin-techdocs-node","fixedVersion":"1.15.4"}],"fix":{"url":"https://github.com/backstage/backstage/commit/02cd7cdbb18b687446277b5602adaee7f1d53cbb","label":"backstage/backstage@02cd7cd"},"references":[{"type":"WEB","url":"https://github.com/backstage/backstage/releases/tag/v1.50.5"},{"type":"WEB","url":"https://github.com/backstage/backstage/releases/tag/v1.54.6"},{"type":"ADVISORY","url":"https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/106xxx/CVE-2026-106509.json"},{"type":"ADVISORY","url":"https://github.com/backstage/backstage/security/advisories/GHSA-8w7q-29mw-gf5c"},{"type":"ADVISORY","url":"https://nvd.nist.gov/vuln/detail/CVE-2026-106509"},{"type":"FIX","url":"https://github.com/backstage/backstage/commit/02cd7cdbb18b687446277b5602adaee7f1d53cbb"},{"type":"FIX","url":"https://github.com/backstage/backstage/commit/a900a9953c8f7ad3ba1906d1d257725a9996cc9d"},{"type":"PACKAGE","url":"https://github.com/backstage/backstage"}],"provenance":{"sources":["OSV.dev","FIRST.org (EPSS)"],"lastVerified":"2026-10-09T02:30:49.320602053Z"}}