CVE-2026-10090 Red Hat CVE debrief

Who should care

Red Hat Advanced Cluster Management for Kubernetes (ACM) users and administrators, especially those with namespace-scoped 'edit' privileges in ACM hub namespaces, should verify and restrict these privileges to prevent potential cluster-admin privilege escalation. Additionally, ACM documentation should be reviewed and updated to reflect accurate privilege escalation risks. Security teams and vulnerability management teams should also be aware of the potential risks and implement compensating controls to detect and prevent cluster-scoped resource creation.

Technical summary

A flaw in the Application Subscription controller of Red Hat Advanced Cluster Management for Kubernetes (ACM) allows a user with namespace-scoped 'edit' privileges to create Channel and Subscription resources pointing to a controlled Helm repository, leading to potential cluster-admin privilege escalation. The app-subscription controller fetches and applies the Helm chart contents with its own elevated authority, without verifying whether the subscription creator holds the 'open-cluster-management:subscription-admin' role and without restricting applied resources to the subscription namespace.

Defensive priority

Full cluster-admin privilege escalation possible; verify and restrict namespace-scoped 'edit' privileges in ACM hub namespaces.

Recommended defensive actions

• Verify and restrict namespace-scoped 'edit' privileges in ACM hub namespaces
• Monitor for and restrict creation of Channel and Subscription resources pointing to untrusted Helm repositories
• Implement compensating controls to detect and prevent cluster-scoped resource creation
• Review and update ACM documentation to reflect accurate privilege escalation risks
• Apply vendor remediation and patches for the Application Subscription controller vulnerability

Evidence notes

Evidence from Red Hat and NVD indicates a flaw in Application Subscription controller of Red Hat Advanced Cluster Management for Kubernetes (ACM); user with namespace-scoped 'edit' privileges can create Channel and Subscription resources to escalate privileges. The attacker can include cluster-scoped resources in the Helm chart, such as a ClusterRoleBinding granting the attacker's ServiceAccount the 'cluster-admin' ClusterRole. Successful exploitation results in full cluster-admin privilege escalation. This contradicts the ACM documentation which states that non-subscription-admin users should have resources deployed into the subscription namespace only. Defenders should verify namespace-scoped 'edit' privileges in ACM hub namespaces and restrict creation of Channel and Subscription resources pointing to untrusted Helm repositories.

Official resources