Backstage has improper input validation in scaffolder task list ordering

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-2026-106506: 0.22% estimated exploitation activity in the next 30 days; percentile 12.31 (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 with permission to create and read relevant scaffolder tasks may be able to infer confidential task data under specific conditions. Successful exploitation requires retained task secrets, visibility of a target task, knowledge of the secret structure, and repeated requests. Patches Patched in @backstage/plugin-scaffolder-backend version 4.1.0 Workarounds - At the gateway or reverse proxy, reject task-list requests that specify custom ordering, or allow ordering only by createdat, status, and createdby. - Restrict scaffolder task creation and task read permissions to trusted users, preferably using owner-based task-read conditions. - Disabling task recovery can reduce secret retention after a task is claimed, but it does not protect secrets in queued tasks and should not be treated as complete mitigation.

Published by the source

7 Oct 2026, 16:24 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-vwp5-f99x-x3rq

2. Revision 2 · amended · 24 Oct 2026

   Amended from osv record GHSA-vwp5-f99x-x3rq

3. Revision 1 · created · 23 Oct 2026

   Published from ghsa record GHSA-vwp5-f99x-x3rq

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# Patch Next advisory brief: CVE-2026-106506

Advisory: Backstage has improper input validation in scaffolder task list ordering
IDs: CVE-2026-106506, GHSA-vwp5-f99x-x3rq
Record: https://patchnext.com/advisories/cve-2026-106506 (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-scaffolder-backend 4.1.0. A vendor fix does not mean a deployment is fixed.

## Affected components
- npm @backstage/plugin-scaffolder-backend: affected < 4.1.0; fixed in 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-vwp5-f99x-x3rq (GitHub-reviewed advisory GHSA-vwp5-f99x-x3rq lists affected ranges: npm @backstage/plugin-scaffolder-backend >=0 <4.1.0)
- Verified: https://osv.dev/vulnerability/GHSA-vwp5-f99x-x3rq (OSV record GHSA-vwp5-f99x-x3rq lists affected ranges: npm @backstage/plugin-scaffolder-backend >=0 <4.1.0 (fixed))

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