CVE-2026-10090

Red Hat Advanced Cluster Management (ACM) can automatically deploy applications based on “subscriptions.”

This bug lets a person with limited permissions in one part of your ACM “hub” trick ACM into deploying a Helm package they control. Because ACM trusts the instruction and applies it with powerful permissions, the attacker can end up with “cluster-admin” control—like getting the master keys to your entire Kubernetes management setup.

This matters if you run Red Hat Advanced Cluster Management for Kubernetes (ACM) and you have users with “edit” privileges in an ACM hub namespace (not necessarily subscription-admin rights).

The risk is only relevant when an attacker can use those “edit” permissions to create an Application Subscription pointing to content they control; it is not described as needing user clicks. The findings also note network-based access, but the key gate is having the namespace “edit” privileges on the hub cluster.

This should be treated as urgent because the flaw allows privilege escalation to full cluster-admin control by abusing ACM’s subscription deployment mechanism. Even without confirmed public exploitation, this is a critical access-control bypass that can enable central, organization-wide takeover once a capable insider (or compromised account) has the required “edit” permissions.

1. Confirm exposure in your environment

   • Determine your ACM version(s). The affected versions are: 2.11, 2.13, 2.14, 2.15, 2.16, 2.17.
   • In the ACM hub cluster, check who has “edit” privileges in namespaces relevant to application subscription management.

2. Validate whether risky subscription behavior is present

   • Review audit logs / Kubernetes events for Application Subscription creations and the related Helm chart fetch/apply actions.
   • Pay special attention to creations originating from users who are not subscription administrators, then look for any resulting cluster-scoped objects (for example, ClusterRoleBindings) created as a result of those subscriptions.

3. Patch to the fixed versions (preferred)

   • Upgrade ACM to one of the fixed builds listed below (pick the one corresponding to your current minor version):
     • Red Hat Advanced Cluster Management for Kubernetes 2.11 → fixed in 1787263584
     • Red Hat Advanced Cluster Management for Kubernetes 2.13 → fixed in 1787263693
     • Red Hat Advanced Cluster Management for Kubernetes 2.14 → fixed in 1787170830
     • Red Hat Advanced Cluster Management for Kubernetes 2.15 → fixed in 1787240030
     • Red Hat Advanced Cluster Management for Kubernetes 2.16 → fixed in 1787242321
     • Red Hat Advanced Cluster Management for Kubernetes 2.17 → fixed in 1787242108

4. Temporary workaround if you cannot upgrade immediately

   • Remove the RBAC aggregation described in the findings by deleting the ClusterRole that aggregates Application Subscription management permissions into the Kubernetes edit role:
     • oc delete clusterrole open-cluster-management:multicloud-operators-subsc
   • After applying the workaround, re-check that non-subscription-admin users no longer have the ability to manage Application Subscription deployments via the aggregated permissions.

5. Ongoing monitoring after mitigation

   • Continue monitoring for Application Subscription changes and for unexpected cluster-scoped RBAC resources created via subscription deployments.
   • If you find suspicious or unknown subscriptions created by non-subscription-admin users, treat the involved accounts and any referenced Helm repositories as potentially compromised and rotate credentials as appropriate.

6. CISA timeline

   • KEV listing is not provided for this CVE in the supplied findings, so no CISA due date was identified here.

Severity is critical (CVSS 9 in the prompt). This is an authorization failure: a user with namespace-scoped “edit” permissions in an ACM hub namespace can create an Application Subscription that references attacker-controlled Helm content.

Mechanism: the multicluster-operators-subscription/Application Subscription controller fetches and applies the Helm chart using elevated authority without sufficiently verifying that the subscription creator has the intended subscription-admin role (and without restricting the applied resources to safe/namespace-limited scope). This permits including cluster-scoped Kubernetes resources in the chart, such as a ClusterRoleBinding granting the attacker’s identity the cluster-admin ClusterRole.

Exploitation status: no KEV listing was provided and the findings report no clear dated press claim and no public exploit code on record; however, the traffic-light verdict for this CVE is RED, and the issue directly enables full cluster-admin escalation when the attacker can obtain the required hub-namespace “edit” permissions.

EPSS is given as a prediction only and is not used as deciding evidence (findings indicate it is flat at 0.4%).