Backstage: Sensitive information exposure in Scaffolder

Exploitation

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

CVSS

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

EPSS

• CVE-2026-106501: 0.48% estimated exploitation activity in the next 30 days; percentile 41.73 (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 An authenticated Backstage user who can read another user's Scaffolder task may receive internal execution data. In deployments where that data contains credentials for an external service, this may permit disclosure and unauthorized changes in that external service. Patches Patched in @backstage/plugin-scaffolder-backend version 4.1.0 Workarounds - Configure scaffolder.task.read with the isTaskOwner condition so users can only read tasks they created. - Restrict affected integrations and workflows to trusted operators until an upgrade is available.

Published by the source

7 Oct 2026, 17:59 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-g2v8-7jhw-pp8p

2. Revision 2 · amended · 24 Oct 2026

   Amended from osv record GHSA-g2v8-7jhw-pp8p

3. Revision 1 · created · 23 Oct 2026

   Published from ghsa record GHSA-g2v8-7jhw-pp8p

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# Patch Next advisory brief: CVE-2026-106501

Advisory: Backstage: Sensitive information exposure in Scaffolder
IDs: CVE-2026-106501, GHSA-g2v8-7jhw-pp8p
Record: https://patchnext.com/advisories/cve-2026-106501 (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: Critical (CVSS 9.6)
Exploitation: no confirmed exploitation recorded. Patch Next confirms exploitation only from CISA KEV.
Vendor response: Vendor fix available; fixed versions by package: @backstage/plugin-scaffolder-backend 4.1.0, 4.0.3, 3.4.1, 3.3.1. A vendor fix does not mean a deployment is fixed.

## Affected components
- npm @backstage/plugin-scaffolder-backend: affected < 3.3.1; >= 3.4.0, < 3.4.1; >= 4.0.0, < 4.0.3; >= 4.0.4, < 4.1.0; fixed in 3.3.1, 3.4.1, 4.0.3, 4.1.0

## Suggested inspection (read-only)
- `npm ls @backstage/plugin-scaffolder-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-scaffolder-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-g2v8-7jhw-pp8p (GitHub-reviewed advisory GHSA-g2v8-7jhw-pp8p lists affected ranges: npm @backstage/plugin-scaffolder-backend >=0 =3.4.0 =4.0.0 =4.0.4 <4.1.0)
- Verified: https://osv.dev/vulnerability/GHSA-g2v8-7jhw-pp8p (OSV record GHSA-g2v8-7jhw-pp8p lists affected ranges: npm @backstage/plugin-scaffolder-backend >=0 =3.4.0 =4.0.0 =4.0.4 <4.1.0 (fixed))

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