CVE-2026-32236 — @backstage/plugin-auth-ba…
Fix: backstage/backstage@17038abCVE-2026-32236 is a Server-Side Request Forgery (SSRF) vulnerability in @backstage/plugin-auth-backend. A fix is available for @backstage/plugin-auth-backend — see the affected versions and patch details below.
@backstage/plugin-auth-backend: SSRF in experimental CIMD metadata fetch
Exploitation Status
No confirmed exploitation observed yet
- CISA’s own triage has not observed active exploitation or public proof-of-concept code for this CVE as of its last assessment.
Exploitation and automatability from CISA’s SSVC triage for CVE-2026-32236.
EPSS Exploitation Probability
EPSS (Exploit Prediction Scoring System) is a daily probability model maintained by FIRST.org. It estimates the likelihood a CVE will be exploited in production environments within the next 30 days, derived from real-world threat intelligence signals.
Real-World Exposure
How broadly this vulnerability is actually deployed: weekly install volume shows current usage, and reverse-dependency count shows how many other packages break if it stays unpatched.
@backstage/plugin-auth-backendnpmDescription
Impact
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.
Patches
Patched in @backstage/plugin-auth-backend version 0.27.1. The fix disables HTTP redirect following when fetching CIMD metadata documents.
Workarounds
Disable the experimental CIMD feature by removing or setting auth.experimentalClientIdMetadataDocuments.enabled to false in your app-config. This is the default configuration.
Alternatively, restrict allowedClientIdPatterns to specific trusted domains rather than using the default wildcard pattern.
References
Affected Packages
| Ecosystem | Package | Vulnerable range | Fix |
|---|---|---|---|
| 📦npm | @backstage/plugin-auth-backend | all versions | 0.27.1npm install @backstage/plugin-auth-backend@0.27.1 |
Detection & mitigation playbook
Open-source dependencyDetect
Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for @backstage/plugin-auth-backend, including transitive dependencies — a direct dependency you never call can still pull in a vulnerable version.
Fix
Update @backstage/plugin-auth-backend to 0.27.1 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms CVE-2026-32236 is resolved across your whole dependency graph.
Workarounds
If you can't upgrade right away: gate or disable the affected feature, validate untrusted input at the boundary, and avoid passing attacker-controlled data into the vulnerable path. O3's runtime protection blocks exploitation in production as an interim safeguard until the upgrade lands.
How O3 protects you
O3 Security's impact-aware SCA analyses which vulnerable code paths your application actually calls, so a match like CVE-2026-32236 can be triaged on real exposure rather than presence alone.
Tailored to CVE-2026-32236. Runtime protection reduces exposure until a permanent patch is applied and verified — it complements patching, it doesn't replace it.
Frequently Asked Questions
Is CVE-2026-32236 in your dependencies?
O3 Security finds CVE-2026-32236 across npm dependencies, including transitive ones, and its impact-aware SCA ranks findings by whether your code actually calls the vulnerable path.