Backstage: Improper input validation in TechDocs static content requests

Exploitation

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

CVSS

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

EPSS

• CVE-2026-106490: 0.37% estimated exploitation activity in the next 30 days; percentile 30.91 (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 Azure Blob Storage provider, an authenticated Backstage user may be able to read restricted TechDocs content when entity-level permissions are enabled. Deployments that intentionally disable the default backend authentication policy may have broader exposure. Patches Patched in @backstage/plugin-techdocs-backend version 2.2.4 Workarounds - Restrict access to the TechDocs backend to users who are permitted to view all stored documentation until an upgrade can be applied. - Keep the default backend authentication policy enabled.

Published by the source

7 Oct 2026, 18:00 UTC

Last modified by the source

7 Oct 2026, 18:15 UTC

Source last checked

26 Oct 2026, 13:07 UTC

1. Revision 3 · amended · 26 Oct 2026

   Amended from ghsa record GHSA-7mfx-xg57-53c9

2. Revision 2 · amended · 24 Oct 2026

   Amended from osv record GHSA-7mfx-xg57-53c9

3. Revision 1 · created · 23 Oct 2026

   Published from ghsa record GHSA-7mfx-xg57-53c9

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# Patch Next advisory brief: CVE-2026-106490

Advisory: Backstage: Improper input validation in TechDocs static content requests
IDs: CVE-2026-106490, GHSA-7mfx-xg57-53c9
Record: https://patchnext.com/advisories/cve-2026-106490 (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 6.5)
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-backend 2.2.4. A vendor fix does not mean a deployment is fixed.

## Affected components
- npm @backstage/plugin-techdocs-backend: affected < 2.2.4; fixed in 2.2.4

## Suggested inspection (read-only)
- `npm ls @backstage/plugin-techdocs-backend --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-backend.
- 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-7mfx-xg57-53c9 (GitHub-reviewed advisory GHSA-7mfx-xg57-53c9 lists affected ranges: npm @backstage/plugin-techdocs-backend >=0 <2.2.4)
- Verified: https://osv.dev/vulnerability/GHSA-7mfx-xg57-53c9 (OSV record GHSA-7mfx-xg57-53c9 lists affected ranges: npm @backstage/plugin-techdocs-backend >=0 <2.2.4 (fixed))

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