A crafted Subscription annotation lets a low-privileged user on a managed Kubernetes cluster hijack the subscription controller's Service Account and deploy resources into any namespace, scoring a 9.9 CVSS.
What Is It
A flaw in the multicloud-operators-subscription component allows a user on a managed cluster to escalate privileges by creating a Subscription object with specific, crafted annotations. The controller processes those annotations without adequate authorization checks, and the resulting deployment action runs with the elevated permissions of the controller's Service Account rather than those of the requesting user.
Red Hat assigned a CVSS 3.1 base score of 9.9 (Critical) with vector CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:C/C:H/I:H/A:H, network-attackable, low complexity, only low privileges required, no user interaction, and a changed scope, reflecting the break out of the attacker's own namespace boundary.
Why It Matters
Successful exploitation grants the ability to deploy arbitrary resources into any namespace on the cluster with Service Account-level permissions, potentially leading to unauthorized access and control over cluster resources. The required starting position is minimal: any user who can create a Subscription on a managed cluster. In multi-tenant clusters, this collapses namespace isolation, the primary tenancy boundary, and turns a routine application-deployment primitive into a cluster-wide control path.
What's Vulnerable
Red Hat lists the following as affected:
- Red Hat Advanced Cluster Management for Kubernetes 2:
multicluster-operators-subscription-rhel9,multicluster-operators-application-rhel9,search-collector-rhel9 - Multicluster Global Hub:
multicluster-globalhub-agent-rhel9,multicluster-globalhub-manager-rhel9,multicluster-globalhub-rhel9-operator - Red Hat OpenShift Container Platform 4:
topology-aware-lifecycle-managerimages (rhel8/rhel9 operator, recovery, aztp),lifecycle-agentoperator images,ztp-site-generate-rhel8,cnf-tests-rhel8
Marked unaffected: the RHACM 2 governance policy components (governance-policy-propagator-rhel9, config-policy-controller-rhel9, cert-policy-controller-rhel9, acm-governance-policy-framework-addon-rhel9) and OpenShift Data Foundation 4 packages including odf-cli-rhel9.
Patch Status
No fixed versions have shipped yet, and Red Hat has published no mitigation or workaround for the affected products. Until errata land, defenders should treat Subscription-creation rights on managed clusters as a privileged capability: audit which users and service accounts hold create on Subscription objects, restrict that permission to trusted principals, and watch for Subscription objects carrying unexpected annotations or targeting namespaces outside the requester's tenancy. Track the Red Hat security page and Bugzilla entry below for errata as they ship.
Sources
- Red Hat Security; CVE-2026-66792: https://access.redhat.com/security/cve/CVE-2026-66792
- Red Hat Bugzilla; Bug 2507537: https://bugzilla.redhat.com/show_bug.cgi?id=2507537