CVE-2026-106501: Backstage: Sensitive information exposure in Scaffolder

Severity: critical (CVSS 9.6 v3.1)
Exploited in the wild: not listed in CISA KEV
EPSS: 0.5% probability of exploitation in the next 30 days
Public exploit or detection template: none known
Published: 2026-10-06 · updated 2026-10-13
Weakness: CWE-200

Description

Backstage is an open framework for building developer portals. Prior to 3.3.1, 3.4.1, 4.0.3 and 4.1.0, the @backstage/plugin-scaffolder-backend package is affected by sensitive information exposure in scaffolder. 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. This issue is fixed in versions 3.3.1, 3.4.1, 4.0.3 and 4.1.0.

Affected products

backstage: before 1.49.6; from 1.50.0 before 1.50.5; from 1.51.0 before 1.54.6 — fixed in 1.49.6, 1.50.5, 1.54.6
@backstage plugin-scaffolder-backend: before 3.3.1; from 3.4.0 before 3.4.1; from 4.0.0 before 4.0.3; from 4.0.4 before 4.1.0 — fixed in 3.3.1, 3.4.1, 4.0.3, 4.1.0

How to fix

Upgrade to a fixed version: backstage 1.49.6, 1.50.5, 1.54.6; @backstage plugin-scaffolder-backend 3.3.1, 3.4.1, 4.0.3, 4.1.0. Check the vendor advisory for mitigations.

References

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