CVE-2026-32236 @backstage/plugin-auth-backend: SSRF in experimental CIMD metadata fetch
An SSRF vulnerability in the Backstage auth plugin allows bypassing IP restrictions during redirects when an experimental feature is enabled.
- Exploited in the wild
- Not known
- Login needed
- Not needed
- Attackable
- Over the internet
- Victim action needed
- Not needed
- Fix
- Available
What is CVE-2026-32236?
CVE-2026-32236 is a low-severity server-side request forgery vulnerability in Linuxfoundation Backstage, published on 12 Mar 2026. An attacker can exploit it over the internet without logging in, with no action from the victim.
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.
Weakness: CWE-918
Which versions are affected by CVE-2026-32236?
2 open source packages ship an affected version, including @backstage/plugin-auth-backend. It affects 1 product.
| Package | Affected | Fixed in |
|---|---|---|
@backstage/plugin-auth-backend npm | All versions | 0.27.1 |
@backstage/plugin-auth-backend npm | All versions | 0.27.1 |
Products include Linuxfoundation Backstage.
How do I fix CVE-2026-32236?
Upgrade @backstage/plugin-auth-backend to 0.27.1 or later.
Upgrade, and send outbound requests through an allow-list that blocks internal addresses. More about Server-side request forgery.
Is CVE-2026-32236 being exploited?
There is no known exploitation of CVE-2026-32236 in the wild and no public exploit code.
Other vulnerabilities in Linuxfoundation Backstage
- CVE-2026-106501 Backstage: Sensitive information exposure in Scaffolder
- CVE-2026-106558 Backstage: Improper validation of TechDocs MkDocs configuration
- CVE-2026-88064 Backstage: Improper input validation in TechDocs MkDocs configuration
- CVE-2026-106459 Backstage: Improper input validation in Sentry scaffolder actions
- CVE-2026-106486 Backstage: Improper filesystem validation in Bitbucket pull-request scaffolder actions
Sources
Also known as GHSA-qp4c-xg64-7c6x, ROOT-APP-NPM-CVE-2026-32236.