CVE-2026-10090: Multicluster-operators-subscription: namespace edit user can deploy cluster-scoped clusterrolebinding and become cluster-admin via application subscription

1. In CISA KEV: not seen
2. Exploited (reported): not seen
3. Scanning observed: not seen
4. Proof of concept public: not seen
5. Not establishedNothing in the sources we check

DescriptionNVD

A flaw was found in the Application Subscription controller (multicluster-operators-subscription) of Red Hat Advanced Cluster Management for Kubernetes (ACM). A user with namespace-scoped "edit" privileges in an ACM hub namespace can create a Channel resource pointing to a Helm repository they control and a Subscription resource referencing it. 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. This allows the attacker to 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.

Exploitation

Unlikely (under 1%). EPSS under 1%, or no score yet.

CISA KEV

Not listed

Public check

No public nuclei template

Weakness

Privilege Defined With Unsafe Actions · Access Control

Vendor

Red Hat

Published

August 2026

Band

Unlikely (under 1%), August 2026

• NVD entrynvd.nist.gov
• Vendor advisoryaccess.redhat.com
• CVE recordcve.org
• Weakness CWE-267cwe.mitre.org