Vulnerability in Backstage Framework for Dynamic Client Registration and Client ID Metadata
CVE-2026-73563

4.7MEDIUM

Key Information:

Vendor

Backstage

Status
Backstage
Vendor
CVE Published:
13 August 2026

What is CVE-2026-73563?

The Backstage framework includes vulnerabilities in its experimental dynamic client registration features, which may allow attackers to exploit wildcard hostname matching within redirect URIs. Specifically, a misconfiguration of allowlist patterns can enable attackers to manipulate trusted hostname suffixes, leading to unauthorized OAuth authorization code retrieval. Additionally, patterns lacking explicit protocols may permit unintended protocol usage, while redirect URIs containing embedded credentials are improperly validated during the matching process. These features are disabled by default, meaning only custom-configured environments enabling these options are at risk. The issue has been addressed starting from version 0.29.2.

Affected Version(s)

backstage < 0.29.2

References

https://github.com/backstage/backstage/security/advisorie...
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CVSS V3.1

Score:
4.7
Severity:
MEDIUM
Confidentiality:
Low
Integrity:
None
Availability:
Low
Attack Vector:
Network
Attack Complexity:
Low
Privileges Required:
None
User Interaction:
Required
Scope:
Changed

Timeline

  • Vulnerability published

  • Vulnerability Reserved

.