Auth bypass in @Backstage Backend-Defaults
CVE-2026-106492
Backstage is an open framework for building developer portals. Prior to 0.16.1 and 0.17.8, the @backstage/backend-defaults package is affected by improper preservation of access restrictions during service credential delegation. An external service credential configured with access restrictions (e.g., read-only) could bypass those restrictions by routing requests through plugin delegation paths. This could allow a restricted service to perform operations beyond its intended scope, including write operations on plugins it was restricted to read-only access for. This issue is fixed in versions 0.16.1 and 0.17.8.
Vulnerability class: Privilege Escalation
Published .
CVSS v3 metric
CVSS v3 base score 7.6 (High). Vector: CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:L/I:H/A:L.
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 Backend-Defaults — versions < 0.16.1, >= 0.17.0, < 0.17.8
- Backstage — versions < 1.49.6, >= 1.50.0-next.0, < 1.54.6
Weakness classification (CWE)
References
- github.com/backstage/backstage/security/advisories/GHSA-cq7v-rfgc-5c7v
- github.com/backstage/backstage/commit/40346245c53e1bf26dee56601e95c5c4ab9cc124
- github.com/backstage/backstage/commit/bc80ffdafbc92ff7b8c72347eace13cb8688fd33
- github.com/backstage/backstage/releases/tag/v1.49.6
- github.com/backstage/backstage/releases/tag/v1.54.6
Frequently asked questions
- What is CVE-2026-106492?
- CVE-2026-106492 is a high-severity vulnerability in @Backstage Backend-Defaults, classified under Improper Privilege Management. CVSS score: 7.6/10. Published 2026-10-06.
- How severe is CVE-2026-106492?
- High severity. CVSS v3 base score is 7.6 out of 10.