Vulnerability Description
Backstage is an open framework for building developer portals. Prior to 0.27.1, the experimental OIDC provider in @backstage/plugin-auth-backend is vulnerable to a redirect URI allowlist bypass. Instances that have enabled experimental Dynamic Client Registration or Client ID Metadata Documents and configured allowedRedirectUriPatterns are affected. A specially crafted redirect URI can pass the allowlist validation while resolving to an attacker-controlled host. If a victim approves the resulting OAuth consent request, their authorization code is sent to the attacker, who can exchange it for a valid access token. This requires victim interaction and that one of the experimental features is explicitly enabled, which is not the default. This vulnerability is fixed in 0.27.1.
CVSS Score
MEDIUM
Affected Products
| Vendor | Product | Versions |
|---|---|---|
| Linuxfoundation | Backstage | <= 0.27.0 |
Related Weaknesses (CWE)
References
FAQ
What is CVE-2026-32235?
CVE-2026-32235 is a vulnerability with a CVSS score of 5.9 (MEDIUM). Backstage is an open framework for building developer portals. Prior to 0.27.1, the experimental OIDC provider in @backstage/plugin-auth-backend is vulnerable to a redirect URI allowlist bypass. Insta...
How severe is CVE-2026-32235?
CVE-2026-32235 has been rated MEDIUM with a CVSS base score of 5.9/10. Review the CVSS metrics above for detailed severity breakdown.
Is there a patch for CVE-2026-32235?
Check the references section above for vendor advisories and patch information. Affected products include: Linuxfoundation Backstage.