Steeltoe: Header-forwarded client cert lacks proof of private-key possession
Published Sep 17, 2026 · Updated Nov 3, 2026
Original summary
Normalized public record · Updated Nov 3, 2026
Steeltoe: Header-forwarded client cert lacks proof of private-key possession
Publisher and source text is retained separately from QFinch interpretation.
QFinch assessment
When Steeltoe's certificate-based authorization (UseCertificateAuthorization) is configured, the default configuration of the middleware relies on the X-Client-Cert HTTP header to identify the client certificate, without verifying private-key possession. This header is not stripped by common Cloud Foundry routers (like Gorouter or Envoy) on inbound requests.
Potential impact
An attacker who obtains the public certificate of an application instance in the target organization or space can spoof the X-Client-Cert header. This allows the attacker to bypass SameOrg and SameSpace authorization policies, granting unauthorized access to protected endpoints for the duration of the certificate's validity period.
Evidence: public source recordsAffected products
| Affected package, product or range | Fix status |
|---|---|
| Consult the referenced vendor advisory for affected versions. | Consult source advisory |
Matching a version is only one part of assessing exposure. QFinch has not assessed your environment on this public page.
Remediation
Apply the vendor-supported fixed release or mitigation, then verify the affected component is no longer reachable.
- Confirm the affected product and reachable code path exist in your environment.
- Apply the vendor-supported patch or mitigation from the primary advisory.
- Rescan the exact deployed revision and retain verification evidence.
Evidence coverage
- SSVC priority
- LOW
- Confidence
- Not available
- Aliases
- None reported
Scores appear only when corresponding evidence exists. Missing data is never interpreted as zero risk.
Sources and record history
Record history
Published Sep 17, 2026 · Last refreshed Nov 3, 2026