Backstage: Improper validation of MkDocs theme configuration in TechDocs

### Impact 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. ### Patches Patched in `@backstage/plugin-techdocs-node` version `1.15.4` ### Workarounds - Configure TechDocs with `techdocs.generator.runIn: 'docker'` instead of `'local'` to provide container isolation, though this does not fully mitigate the risk. - Restrict write access to repositories registered in the Backstage catalog to trusted users.

Source published

7 Oct 2026 16:23:30 UTC

Source modified

7 Oct 2026 16:30:04 UTC

Observed here

24 Oct 2026 13:17:17 UTC

Source terms

GitHub Advisory Database · CC-BY-4.0

Original source record · Cite this exact observation · Complete original publisher JSON

This view projects the publisher's source fields for reading; the original JSON retains additional fields and CVE enrichment containers. Attribution: osv · GitHub Advisory Database · CC-BY-4.0. Source text is retained; field grouping and change labels are provided by ChangeIntel.

CVSS_V3 · CVSS:3.1/AV:N/AC:H/PR:L/UI:N/S:C/C:H/I:L/A:L

Publisher rating · HIGH