{"id":"CVE-2026-106509","aliases":["EUVD-2026-94074","GHSA-8w7q-29mw-gf5c"],"status":"published","title":"Backstage: Improper validation of MkDocs theme configuration in TechDocs","description":"Backstage is an open framework for building developer portals. Prior to 1.14.6, the @backstage/plugin-techdocs-node package is affected by improper validation of mkdocs theme configuration in techdocs. When 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. This issue is fixed in versions 1.14.6 and 1.15.4.","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":"2026-11-12","score":0.00516,"percentile":0.44448,"model":"v2026.06.15"},"facts":{"in_kev":false,"known_exploited":false,"public_exploit":false,"fix_available":true},"cwes":["CWE-1336","CWE-94"],"published":"2026-10-06T21:50:07Z","modified":"2026-10-28T02:30:26Z","fixes":[{"ecosystem":"npm","package":"@backstage/plugin-techdocs-node","fixed_in":["1.15.4"],"sources":["ghsa","osv"]}],"affected":[{"source":"ghsa","ecosystem":"npm","package":"@backstage/plugin-techdocs-node","ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"},{"fixed":"1.15.4"}]}]},{"source":"osv","ecosystem":"npm","package":"@backstage/plugin-techdocs-node","ranges":[{"type":"SEMVER","events":[{"introduced":"0"},{"fixed":"1.15.4"}]}]}],"products":[{"vendor":"@backstage","product":"plugin-techdocs-node"},{"vendor":"backstage","product":"backstage"},{"vendor":"linuxfoundation","product":"backstage"},{"vendor":"linuxfoundation","product":"backstage_plugin-techdocs-node"}],"references":[{"url":"https://github.com/backstage/backstage/security/advisories/GHSA-8w7q-29mw-gf5c","tags":["x_refsource_CONFIRM","Vendor Advisory","Mitigation","advisory","web"]},{"url":"https://github.com/backstage/backstage/commit/02cd7cdbb18b687446277b5602adaee7f1d53cbb","tags":["x_refsource_MISC","Exploit","Patch","fix","web"]},{"url":"https://github.com/backstage/backstage/commit/a900a9953c8f7ad3ba1906d1d257725a9996cc9d","tags":["x_refsource_MISC","Exploit","Patch","fix","web"]},{"url":"https://github.com/backstage/backstage/releases/tag/v1.50.5","tags":["x_refsource_MISC","Release Notes","web"]},{"url":"https://github.com/backstage/backstage/releases/tag/v1.54.6","tags":["x_refsource_MISC","Release Notes","web"]},{"url":"https://nvd.nist.gov/vuln/detail/CVE-2026-106509","tags":["advisory"]},{"url":"https://github.com/advisories/GHSA-8w7q-29mw-gf5c"},{"url":"https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/106xxx/CVE-2026-106509.json","tags":["advisory"]},{"url":"https://github.com/backstage/backstage","tags":["package"]}],"sources":{"cve":[{"id":"CVE-2026-106509","title":"Backstage: Improper validation of MkDocs theme configuration in TechDocs","description":"Backstage is an open framework for building developer portals. Prior to 1.14.6, the @backstage/plugin-techdocs-node package is affected by improper validation of mkdocs theme configuration in techdocs. When 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. This issue is fixed in versions 1.14.6 and 1.15.4.","status":"published","published":"2026-10-06T21:50:07.721Z","modified":"2026-10-07T18:01:48.511Z","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"}],"cwes":["CWE-94","CWE-1336"],"updated_at":"2026-11-02T14:20:04.156238Z"}],"euvd":[{"id":"EUVD-2026-94074","description":"Backstage is an open framework for building developer portals. Prior to 1.14.6, the @backstage/plugin-techdocs-node package is affected by improper validation of mkdocs theme configuration in techdocs. When 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. This issue is fixed in versions 1.14.6 and 1.15.4.","status":"published","published":"2026-10-06T21:50:07Z","modified":"2026-10-07T18:01:48Z","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"}],"updated_at":"2026-11-02T17:27:34.353796Z"}],"ghsa":[{"id":"GHSA-8w7q-29mw-gf5c","title":"Backstage: Improper validation of MkDocs theme configuration in TechDocs","description":"### 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.","status":"published","published":"2026-10-07T16:23:30Z","modified":"2026-10-07T16:23:31Z","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-94","CWE-1336"],"updated_at":"2026-11-02T14:41:28.013673Z"}],"nvd":[{"id":"CVE-2026-106509","description":"Backstage is an open framework for building developer portals. Prior to 1.14.6, the @backstage/plugin-techdocs-node package is affected by improper validation of mkdocs theme configuration in techdocs. When 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. This issue is fixed in versions 1.14.6 and 1.15.4.","status":"published","published":"2026-10-06T22:17:06.463Z","modified":"2026-10-09T17:34:17.12Z","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":8.8,"vector":"CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H","level":"high","assessor":"primary"}],"cwes":["CWE-94","CWE-1336"],"updated_at":"2026-11-02T14:12:54.809359Z"}],"osv":[{"id":"CVE-2026-106509","title":"Backstage: Improper validation of MkDocs theme configuration in TechDocs","description":"Backstage is an open framework for building developer portals. Prior to 1.14.6, the @backstage/plugin-techdocs-node package is affected by improper validation of mkdocs theme configuration in techdocs. When 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. This issue is fixed in versions 1.14.6 and 1.15.4.","status":"published","published":"2026-10-06T21:50:07.721Z","modified":"2026-10-28T02:30:26.877436476Z","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-1336","CWE-94"],"updated_at":"2026-11-02T15:44:54.583213Z"},{"id":"GHSA-8w7q-29mw-gf5c","title":"Backstage: Improper validation of MkDocs theme configuration in TechDocs","description":"### 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.","status":"published","published":"2026-10-07T16:23:30Z","modified":"2026-10-07T16:30:04.718106469Z","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-1336","CWE-94"],"updated_at":"2026-11-02T15:46:42.78452Z"}]}}