CVE-2026-106503 Backstage @backstage/plugin-scaffolder-backend - Authorization Bypass

Backstage @backstage/plugin-scaffolder-backend < 3.3.1, < 3.4.1, < 4.0.3, and < 4.1.0 contains an authorization bypass caused by improper scaffolder action input validation, letting authenticated users bypass action restrictions and access unauthorized repositories, exploit requires user authentication.

CVSS base score 8.1 /10
High
CISA KEV
Not listed
Public exploit
None known
Authentication
Required
EPSS
0.38% chance of exploitation in 30 days
View the NVD record ↗

Details

Type
Authorization Bypass
Impact
Broken Access Control
CVSS vector
CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:N
Published
6 October 2026
Updated
15 October 2026
Weakness
CWE-178

Vendor fix

Upgrade to versions 3.3.1, 3.4.1, 4.0.3, or 4.1.0 or later.

Patching closes this CVE. It does not tell you which of your systems run the affected version, or what else is exposed alongside them.

References

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