Backstage has potential file exposure through local TechDocs publisher

Exploitation

No confirmed exploitation recorded. Patch Next marks exploitation only from CISA KEV.

CVSS

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

EPSS

• CVE-2026-106508: 0.39% estimated exploitation activity in the next 30 days; percentile 33.10 (FIRST EPSS, 2026-11-03). This is a model estimate, not proof of exploitation or customer exposure.

As published by the source; long descriptions are shortened.

Impact 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. Patches Patched in @backstage/plugin-techdocs-node version 1.15.4 Workarounds If you cannot upgrade immediately, consider switching to an external store for published TechDocs content (e.g. awsS3, googleGcs, or azureBlobStorage publishers)

Published by the source

7 Oct 2026, 16:23 UTC

Last modified by the source

7 Oct 2026, 16:30 UTC

Source last checked

26 Oct 2026, 13:07 UTC

1. Revision 3 · amended · 26 Oct 2026

   Amended from ghsa record GHSA-cm77-ch27-6w6v

2. Revision 2 · amended · 24 Oct 2026

   Amended from osv record GHSA-cm77-ch27-6w6v

3. Revision 1 · created · 23 Oct 2026

   Published from ghsa record GHSA-cm77-ch27-6w6v

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# Patch Next advisory brief: CVE-2026-106508

Advisory: Backstage has potential file exposure through local TechDocs publisher
IDs: CVE-2026-106508, GHSA-cm77-ch27-6w6v
Record: https://patchnext.com/advisories/cve-2026-106508 (revision 3, source checked 26 Oct 2026, 13:07 UTC)
Inventory: none attached. This brief comes from a public page and does not say whether any deployment is affected.
Severity: Medium (CVSS 5.3)
Exploitation: no confirmed exploitation recorded. Patch Next confirms exploitation only from CISA KEV.
Vendor response: Vendor fix available; fixed versions by package: @backstage/plugin-techdocs-node 1.15.4. A vendor fix does not mean a deployment is fixed.

## Affected components
- npm @backstage/plugin-techdocs-node: affected < 1.15.4; fixed in 1.15.4

## Suggested inspection (read-only)
- `npm ls @backstage/plugin-techdocs-node --all`: lists every installed copy and version, including transitive ones. Run in the project root after `npm ci`.

## Supported action
Upgrade each affected component to a fixed version on its release line. For a transitive dependency, upgrade the parent package or add an override or constraint, then regenerate the lockfile. Redeploy every environment that ran an affected version.

## Required regression checks
- Run the test suite and a production build.
- Exercise the features that depend on @backstage/plugin-techdocs-node.
- Repeat the inspection and confirm that only fixed versions remain installed.

## Rollback considerations
- Keep the previous lockfile and deployment artifact. Rolling back reinstates the vulnerable version, so apply any documented mitigation while you fix forward.

## Unresolved questions
- Which deployments run an affected version?
- Exploitation status can change. Check again before lowering the priority.
- Mark the work resolved only after the fixed version is verified in production.

## Sources
- Verified: https://github.com/advisories/GHSA-cm77-ch27-6w6v (GitHub-reviewed advisory GHSA-cm77-ch27-6w6v lists affected ranges: npm @backstage/plugin-techdocs-node >=0 <1.15.4)
- Verified: https://osv.dev/vulnerability/GHSA-cm77-ch27-6w6v (OSV record GHSA-cm77-ch27-6w6v lists affected ranges: npm @backstage/plugin-techdocs-node >=0 <1.15.4 (fixed))

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