GHSA-29gx-h2m3-xw44 CVE-2026-106462
Backstage's scaffolder credential handling may allow unintended GitHub authentication fallback
Medium
npm
- Severity
- 6.4 / 10
- Medium · CVSS 3.1
- Exploit chance (EPSS)
- 0.17%
- Chance of exploitation in the next 30 days. Higher than 6.53% of scored vulnerabilities.
- Known exploited
- No
- Not in CISA's catalog
- Fix
- Available
- 6 packages have a fixed version
Description
Impact
Scaffolder actions that interact with source control systems may not consistently enforce the intended credential boundaries under certain configurations. An authenticated user could perform operations with broader access than intended.
Patches
@backstage/plugin-scaffolder-backendversion4.1.0@backstage/plugin-scaffolder-backend-module-azureversion0.2.25@backstage/plugin-scaffolder-backend-module-bitbucket-cloudversion0.3.10@backstage/plugin-scaffolder-backend-module-bitbucket-serverversion0.2.25@backstage/plugin-scaffolder-backend-module-githubversion0.9.13@backstage/plugin-scaffolder-backend-module-gitlabversion0.11.10
The fix introduces a new configuration option that enforces user-provided credentials for supported SCM actions. The new behavior is opt-in for compatibility. After upgrading, set:
scaffolder:
requireScmUserCredentials: true
Before enabling this setting, review and update your templates as described in the software templates documentation referred to below.
Workarounds
If you cannot upgrade and enable the setting immediately:
- Restrict who can create Scaffolder tasks and which templates they can execute.
- Limit SCM integration credentials to the minimum repository read and mutation permissions required.
- Remove integration credentials for SCM hosts where all required operations can use explicitly supplied user tokens.
Affected versions
npm
| Package | Vulnerable | Fixed in |
|---|---|---|
| @backstage/plugin-scaffolder-backend | < 4.1.0 |
4.1.0 |
| @backstage/plugin-scaffolder-backend-module-azure | < 0.2.25 |
0.2.25 |
| @backstage/plugin-scaffolder-backend-module-bitbucket-cloud | < 0.3.10 |
0.3.10 |
| @backstage/plugin-scaffolder-backend-module-bitbucket-server | < 0.2.25 |
0.2.25 |
| @backstage/plugin-scaffolder-backend-module-github | < 0.9.13 |
0.9.13 |
| @backstage/plugin-scaffolder-backend-module-gitlab | < 0.11.10 |
0.11.10 |
How to fix
Move to the fixed version or later with your package manager, update the lockfile, and run your tests. If the package only arrives through another dependency, upgrade that dependency first. If none of its releases pulls a fixed version yet, force the version with your package manager's override.
@backstage/plugin-scaffolder-backend npm → 4.1.0
- npm
npm install @backstage/plugin-scaffolder-backend@4.1.0- yarn
yarn add @backstage/plugin-scaffolder-backend@4.1.0- pnpm
pnpm add @backstage/plugin-scaffolder-backend@4.1.0
@backstage/plugin-scaffolder-backend-module-azure npm → 0.2.25
- npm
npm install @backstage/plugin-scaffolder-backend-module-azure@0.2.25- yarn
yarn add @backstage/plugin-scaffolder-backend-module-azure@0.2.25- pnpm
pnpm add @backstage/plugin-scaffolder-backend-module-azure@0.2.25
@backstage/plugin-scaffolder-backend-module-bitbucket-cloud npm → 0.3.10
- npm
npm install @backstage/plugin-scaffolder-backend-module-bitbucket-cloud@0.3.10- yarn
yarn add @backstage/plugin-scaffolder-backend-module-bitbucket-cloud@0.3.10- pnpm
pnpm add @backstage/plugin-scaffolder-backend-module-bitbucket-cloud@0.3.10
@backstage/plugin-scaffolder-backend-module-bitbucket-server npm → 0.2.25
- npm
npm install @backstage/plugin-scaffolder-backend-module-bitbucket-server@0.2.25- yarn
yarn add @backstage/plugin-scaffolder-backend-module-bitbucket-server@0.2.25- pnpm
pnpm add @backstage/plugin-scaffolder-backend-module-bitbucket-server@0.2.25
@backstage/plugin-scaffolder-backend-module-github npm → 0.9.13
- npm
npm install @backstage/plugin-scaffolder-backend-module-github@0.9.13- yarn
yarn add @backstage/plugin-scaffolder-backend-module-github@0.9.13- pnpm
pnpm add @backstage/plugin-scaffolder-backend-module-github@0.9.13
@backstage/plugin-scaffolder-backend-module-gitlab npm → 0.11.10
- npm
npm install @backstage/plugin-scaffolder-backend-module-gitlab@0.11.10- yarn
yarn add @backstage/plugin-scaffolder-backend-module-gitlab@0.11.10- pnpm
pnpm add @backstage/plugin-scaffolder-backend-module-gitlab@0.11.10
Severity breakdown
CVSS 3.1 6.4
CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:C/C:L/I:L/A:N
- Attack vector
- Network
- Attack complexity
- Low
- Privileges required
- Low
- User interaction
- None
- Scope
- Changed
- Confidentiality
- Low
- Integrity
- Low
- Availability
- None
Weakness
CWE-441: Unintended Proxy or Intermediary ('Confused Deputy')
The product receives a request, message, or directive from an upstream component, but the product does not sufficiently preserve the original source of the request before forwarding the request to an external actor that is outside of the product's control sphere. This causes the product to appear to be the source of the request, leading it to act as a proxy or other intermediary between the upstream component and the external actor.
How to prevent it
- Architecture and Design: Enforce the use of strong mutual authentication mechanism between the two parties.
- Architecture and Design: Whenever a product is an intermediary or proxy for transactions between two other components, the proxy core should not drop the identity of the initiator of the transaction. The immutability of the identity of the initiator must be maintained and should be forwarded all the way to the target.
CWE-863: Incorrect Authorization
The product performs an authorization check when an actor attempts to access a resource or perform an action, but it does not correctly perform the check.
How to prevent it
- Architecture and Design: Divide the product into anonymous, normal, privileged, and administrative areas. Reduce the attack surface by carefully mapping roles with data and functionality. Use role-based access control (RBAC) [REF-229] to enforce the roles at the appropriate boundaries. Note that this approach may not protect against horizontal authorization, i.e., it will not protect a user from attacking others with the same role.
- Architecture and Design: Ensure that access control checks are performed related to the business logic. These checks may be different than the access control checks that are applied to more generic resources such as files, connections, processes, memory, and database records. For example, a database may restrict access for medical records to a specific database user, but each record might only be intended to be accessible to the patient and the patient's doctor [REF-7].
- Architecture and Design: Use a vetted library or framework that does not allow this weakness to occur or provides constructs that make this weakness easier to avoid. For example, consider using authorization frameworks such as the JAAS Authorization Framework [REF-233] and the OWASP ESAPI Access Control feature [REF-45].
- Architecture and Design: For web applications, make sure that the access control mechanism is enforced correctly at the server side on every page. Users should not be able to access any unauthorized functionality or information by simply requesting direct access to that page. One way to do this is to ensure that all pages containing sensitive information are not cached, and that all such pages restrict access to requests that are accompanied by an active and authenticated session token associated with a user who has the required permissions to access that page.
- System Configuration, Installation: Use the access control capabilities of your operating system and server environment and define your access control lists accordingly. Use a "default deny" policy when defining these ACLs.
References
Advisories
Packages
Other links
Timeline
- Published
- Last updated by the source
- Latest EPSS score
Related advisories
| Advisory | Severity | Why it's related |
|---|---|---|
| GHSA-vwp5-f99x-x3rq Backstage has improper input validation in scaffolder task list ordering | Medium | Also affects @backstage/plugin-scaffolder-backend |
| GHSA-4xvq-3m68-h444 Backstage has sensitive information exposure in scaffolder task logs | Medium | Also affects @backstage/plugin-scaffolder-backend |
| GHSA-hmp2-4m7g-22cv Backstage: Scaffolder action input authorization bypass | High | Also affects @backstage/plugin-scaffolder-backend |
| GHSA-95p4-vv4g-jxxm Backstage may expose sensitive information in Scaffolder task failure events | Medium | Also affects @backstage/plugin-scaffolder-backend |
| GHSA-g2v8-7jhw-pp8p Backstage: Sensitive information exposure in Scaffolder | Critical | Also affects @backstage/plugin-scaffolder-backend |
| GHSA-xvgh-hmx8-9xxf Backstage: Improper task state validation in Scaffolder backend | High | Also affects @backstage/plugin-scaffolder-backend |
| GHSA-mfvq-x7vr-rgqg Backstage: Secret-derived values may be exposed in scaffolder task logs | Medium | Also affects @backstage/plugin-scaffolder-backend |
| GHSA-7hfw-grcm-cqm6 Backstage: Incorrect authorization in scaffolder task listing | Medium | Also affects @backstage/plugin-scaffolder-backend |
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