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

Severity: medium (CVSS 6.5 v3.1)
Exploited in the wild: not listed in CISA KEV
EPSS: 0.4% probability of exploitation in the next 30 days
Public exploit or detection template: none known
Published: 2026-10-06 · updated 2026-10-09
Weakness: CWE-22

Description

Backstage is an open framework for building developer portals. Prior to 1.15.4, the @backstage/plugin-techdocs-node package is affected by potential file exposure through local techdocs publisher. 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. This issue is fixed in version 1.15.4.

Affected products

backstage: before 1.54.6 — fixed in 1.54.6
Linuxfoundation Backstage Plugin-Techdocs-Node: before 1.15.4 — fixed in 1.15.4

How to fix

Upgrade to a fixed version: backstage 1.54.6; Linuxfoundation Backstage Plugin-Techdocs-Node 1.15.4. Check the vendor advisory for mitigations.

References

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