Summary
Backstage: Secret-derived values may be exposed in scaffolder task logs
Workarounds
- Restrict permission to create or update Template entities to fully trusted parties, as recommended by the Backstage threat model.
- If that restriction cannot be guaranteed, remove sensitive values from
scaffolder.defaultEnvironment.secretsuntil a patched version is available.
No complete workaround is known that preserves both untrusted template authoring and access to sensitive default-environment secrets.
Impact
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 in task logs, exposing those values to users with access to the resulting task logs.
CVE-2026-106499 has a CVSS score of 4.9 (Medium). The vector is network-reachable, high privileges required, and no user interaction. A CVSS score reflects the worst-case severity of the vulnerability, not your specific exposure. Whether this affects your application depends on whether the vulnerable code is present and reachable in your environment. A fixed version is available (4.1.0); upgrading removes the vulnerable code path.
Affected versions
Security releases
Kodem intelligence
Severity tells you how bad this could be in the worst case. It does not tell you whether you are exposed. Exploitability and impact are functions of runtime truth: whether the vulnerable code is present, reachable, and actually executes in your application. A vulnerable package can sit in your dependency tree and never run.
Kodem, an Intelligent Application Security platform, uses runtime intelligence to reveal which vulnerabilities actually execute in production, so teams prioritize the ones that genuinely matter. Kodem's runtime-powered SCA identifies whether this CVE is reachable in your applications.
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Patched in @backstage/plugin-scaffolder-backend version 4.1.0
Frequently Asked Questions
- What is CVE-2026-106499? CVE-2026-106499 is a medium-severity security vulnerability in @backstage/plugin-scaffolder-backend (npm), affecting versions < 4.1.0. It is fixed in 4.1.0.
- How severe is CVE-2026-106499? CVE-2026-106499 has a CVSS score of 4.9 (Medium). This score reflects the worst-case severity of the vulnerability, not your specific exposure. Whether it represents real risk in your environment depends on whether the vulnerable code is present and reachable.
- Which versions of @backstage/plugin-scaffolder-backend are affected by CVE-2026-106499? @backstage/plugin-scaffolder-backend (npm) versions < 4.1.0 is affected.
- Is there a fix for CVE-2026-106499? Yes. CVE-2026-106499 is fixed in 4.1.0. Upgrade to this version or later.
- Is CVE-2026-106499 exploitable, and should I be worried? Whether CVE-2026-106499 is exploitable in your environment depends on whether the vulnerable code is present and reachable. A CVSS score is a worst-case rating; it does not account for your specific deployment, configuration, or usage patterns. Kodem, an Intelligent Application Security platform, uses runtime intelligence to show which vulnerabilities actually execute in production, so you can focus on the ones that represent real risk. Get a demo
- What actually determines whether CVE-2026-106499 is exploitable, and how bad it is? Exploitability and impact are not fixed properties of a CVE. They depend on runtime truth: whether the vulnerable code is present, reachable, and actually executes in your application. A high CVSS score on a dependency that never runs is not the same as real risk. Kodem, an Intelligent Application Security platform, uses runtime intelligence to reveal which vulnerabilities actually execute in production, so teams prioritize the ones that genuinely matter.
- How do I fix CVE-2026-106499? Upgrade
@backstage/plugin-scaffolder-backendto 4.1.0 or later.