What is CVE-2026-106499?

CVE-2026-106499 is a medium-severity vulnerability in @Backstage Plugin-Scaffolder-Backend, classified under Insertion of Sensitive Information into Log File. CVSS score: 4.9/10. Published 2026-10-06.

How severe is CVE-2026-106499?

Medium severity. CVSS v3 base score is 4.9 out of 10.

Information disclosure in @Backstage Plugin-Scaffolder-Backend

CVE-2026-106499

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.

Published 2026-10-06 · last modified 2026-10-07.

CVSS v3 metric

CVSS v3 base score 4.9 (Medium). Vector: CVSS:3.1/AV:N/AC:L/PR:H/UI:N/S:U/C:H/I:N/A:N.

EPSS exploit prediction

No EPSS score from FIRST.org yet. New CVEs usually get one within a few days; no score means no signal yet, not low risk. How EPSS works.

Affected products

@Backstage Plugin-Scaffolder-Backend — versions < 4.1.0
Backstage — versions < 1.54.6

Weakness classification (CWE)

CWE-532 — Insertion of Sensitive Information into Log File

References

Frequently asked questions

What is CVE-2026-106499?: CVE-2026-106499 is a medium-severity vulnerability in @Backstage Plugin-Scaffolder-Backend, classified under Insertion of Sensitive Information into Log File. CVSS score: 4.9/10. Published 2026-10-06.
How severe is CVE-2026-106499?: Medium severity. CVSS v3 base score is 4.9 out of 10.