Is CVE-2026-106503 exploited in the wild?

No. Junglewise Threat Intelligence has no report of CVE-2026-106503 being exploited in the wild.

How severe is CVE-2026-106503?

High severity, with a CVSS score of 8.1, published 6 October 2026.

Which products and versions are affected?

Backstage Plugin-Scaffolder-Backend prior to 3.3.1, 3.4.1, 4.0.3 and 4.1.0; @backstage/plugin-scaffolder-backend (npm) SEMVER:introduced=0,fixed=3.3.1.

Is there a fix for CVE-2026-106503?

Yes. @backstage/plugin-scaffolder-backend (npm): upgrade to 3.3.1 or later. Junglewise finds every place you run it, drafts the upgrade and applies it once you approve.

How is CVE-2026-106503 attacked?

It is attacked over the network, in a software library.

Am I affected by CVE-2026-106503?

Check whether you run Backstage Plugin-Scaffolder-Backend or @backstage/plugin-scaffolder-backend (npm) at an affected version. Junglewise does that check for you around the clock: connect your code, cloud and domains, and it matches new vulnerabilities like this one against what you actually run and tells you when one reaches you.

CVE-2026-106503: Backstage Scaffolder Backend authorization bypass in action input validation

CVE-2026-106503 · Severity: high · CVSS 8.1 · Published 2026-10-06

Backstage is an open framework for building developer portals where authenticated users can run templated scaffold actions. A flaw in the Scaffolder Backend plugin allows authenticated users to bypass restrictions on which actions they are permitted to use by manipulating action input validation. An attacker could exploit this to access repositories and source control systems they shouldn't have permission to use.

Technologies: Backstage Plugin-Scaffolder-Backend, @backstage/plugin-scaffolder-backend (npm). Vendors: Backstage, npm.

Quick answers

Is CVE-2026-106503 exploited in the wild?: No. Junglewise Threat Intelligence has no report of CVE-2026-106503 being exploited in the wild.
How severe is CVE-2026-106503?: High severity, with a CVSS score of 8.1, published 6 October 2026.
Which products and versions are affected?: Backstage Plugin-Scaffolder-Backend prior to 3.3.1, 3.4.1, 4.0.3 and 4.1.0; @backstage/plugin-scaffolder-backend (npm) SEMVER:introduced=0,fixed=3.3.1.
Is there a fix for CVE-2026-106503?: Yes. @backstage/plugin-scaffolder-backend (npm): upgrade to 3.3.1 or later. Junglewise finds every place you run it, drafts the upgrade and applies it once you approve.
How is CVE-2026-106503 attacked?: It is attacked over the network, in a software library.
Am I affected by CVE-2026-106503?: Check whether you run Backstage Plugin-Scaffolder-Backend or @backstage/plugin-scaffolder-backend (npm) at an affected version. Junglewise does that check for you around the clock: connect your code, cloud and domains, and it matches new vulnerabilities like this one against what you actually run and tells you when one reaches you.

How to fix

@backstage/plugin-scaffolder-backend (npm): upgrade to 3.3.1 or later
```
npm install @backstage/plugin-scaffolder-backend@3.3.1
```

Technical details

The @backstage/plugin-scaffolder-backend package fails to properly validate action input values against configured permission policies, allowing authenticated users to circumvent action restrictions. The vulnerability requires authentication and is triggered when a user with access to affected Scaffolder templates supplies crafted input that bypasses permission matching logic. An attacker gains the ability to execute restricted scaffold actions and access associated integration credentials.

Affected products

Backstage plugin-scaffolder-backend prior to 3.3.1, 3.4.1, 4.0.3 and 4.1.0

Identifiers

CVE-2026-106503
GHSA-hmp2-4m7g-22cv

Timeline

2026-10-06: disclosed

References

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