CVE-2026-106499: Backstage: Secret-derived values may be exposed in scaffolder task logs

Severity: medium (CVSS 4.9 v3.1)
Exploited in the wild: not listed in CISA KEV
EPSS: 0.3% probability of exploitation in the next 30 days
Public exploit or detection template: none known
Published: 2026-10-06 · updated 2026-10-15
Weakness: CWE-532

Description

Backstage is an open framework for building developer portals. Prior to 4.1.0, the @backstage/plugin-scaffolder-backend package could expose secret-derived values in Scaffolder task logs. Deployments that configure sensitive scaffolder.defaultEnvironment.secrets and allow an attacker to create or modify Scaffolder templates are affected. A template author could cause secret-derived values used during template iteration to be persisted and exposed to users who can access the resulting task logs. This issue is fixed in version 4.1.0.

Affected products

backstage: before 1.54.6 — fixed in 1.54.6
@backstage plugin-scaffolder-backend: before 4.1.0 — fixed in 4.1.0

How to fix

Upgrade to a fixed version: backstage 1.54.6; @backstage plugin-scaffolder-backend 4.1.0. Check the vendor advisory for mitigations.

References

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