CVE-2026-106508: Backstage has potential file exposure through local TechDocs publisher

October 7, 2026

When using the local TechDocs publisher (techdocs.publisher.type: 'local'), it was possible for the documentation serving endpoint to follow filesystem references outside the intended documentation tree, potentially exposing host files to authenticated users.

This is mitigated by the fact that exploration requires preconditions that do not arise through normal MkDocs operation. Cloud-based publishers (S3, GCS, Azure Blob Storage) are not affected.

References

github.com/advisories/GHSA-cm77-ch27-6w6v
github.com/backstage/backstage/commit/6aecb26f337ffec1d4e67ce903cf1e39b6082ec4
github.com/backstage/backstage/releases/tag/v1.54.6
github.com/backstage/backstage/security/advisories/GHSA-cm77-ch27-6w6v
nvd.nist.gov/vuln/detail/CVE-2026-106508

Code Behaviors & Features

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