Vulnerability · Published Mar 12, 2026 · Assigned by GitHub_M
CVE-2026-32236@backstage/plugin-auth-backend: SSRF in experimental CIMD metadata fetch
Low 1.7
In plain English
A low-severity server-side request forgery in plugin-auth-backend from @backstage. There are no confirmed reports of exploitation so far. The chance it is exploited in the next 30 days is estimated at 0.3% (higher than 24% of all known vulnerabilities). Fixed versions are available - upgrade the affected package.
Official description
Backstage is an open framework for building developer portals. Prior to 0.27.1, a Server-Side Request Forgery (SSRF) vulnerability exists in @backstage/plugin-auth-backend when auth.experimentalClientIdMetadataDocuments.enabled is set to true. The CIMD metadata fetch validates the initial client_id hostname against private IP ranges but does not apply the same validation after HTTP redirects. The practical impact is limited. The attacker cannot read the response body from the internal request, cannot control request headers or method, and the feature must be explicitly enabled via an experimental flag that is off by default. Deployments that restrict allowedClientIdPatterns to specific trusted domains are not affected. Patched in @backstage/plugin-auth-backend version 0.27.1.
Affected packages & fixed versions
| Ecosystem | Package | Fixed in | Advisory |
|---|---|---|---|
| npm | @backstage/plugin-auth-backend | 0.27.1 | GHSA-qp4c-xg64-7c6x |
Affected products (as reported)
| Vendor | Product | Versions |
|---|---|---|
| @backstage | plugin-auth-backend | < 0.27.1 |
Weakness: CWE-918 · Vector: CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:N/VC:N/VI:L/VA:N/SC:N/SI:N/SA:N/E:U