Medium [CVE-2026-19130] cross-namespace credential propagation via attacker-controlled copiedFrom labels bypasses authorization

A flaw was found in the provider-credential-controller component of multicluster-engine (MCE). An attacker with specific permissions on the hub cluster, and knowledge of a prior credential value, could exploit an authorization bypass vulnerability.

By manipulating `copiedFrom` labels, the attacker could intercept newly rotated provider credentials, leading to unauthorized information disclosure. This allows access to sensitive credentials that should otherwise be protected.

This vulnerability is rated as having an Important impact in multicluster-engine because unauthorized cross-namespace credential propagation allows low-privileged tenants to compromise updated provider secrets, breaking multi-tenant isolation boundaries.

Although exploitation requires high complexity—namely having Secret creation rights in a namespace, knowing the exact pre-rotation credential value, and awaiting an administrative credential rotation—the resulting compromise grants unauthorized access to sensitive provider infrastructure.

In typical hub cluster environments, Secret creation privileges within individual namespaces are commonly granted to developers or tenant administrators, elevating the risk of credential interception. Red Hat severity: Important — CVSS 5.8 (CVSS:3.1/AV:N/AC:H/PR:L/UI:R/S:C/C:H/I:N/A:N).

Weakness: CWE-639.