CVE-2026-10090

CRITICAL

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

Title source: CVE List
STIX 2.1 vulnerability

Record summary

CVE-2026-10090 has a selected CVSS score of 9.0 (critical).

Description

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.

Description source: CVE List

Exploitation context

CISA SSVC decision

ExploitationNone
AutomatableNo
Technical impactTotal

CISA Coordinator · SSVC 2.0.3 · Evaluated Aug 5, 2026 · Source: CVE List

Affected products and versions

1
ProductSourceVersion range

Red Hat Advanced Cluster Management for Kubernetes 2

Browse Red Hat / Red Hat Advanced Cluster Management for Kubernetes 2rhacm2/multicluster-operators-subscription-rhel9

Default status: affected

CVE ListVersion data not supplied

Research & analysis

1
Advisory analysisRed Hat Product SecuritySource: EIP research review

CVE-2026-10090 - Red Hat Customer Portal

Red Hat advisory details CVE-2026-10090, a privilege escalation flaw in the Application Subscription controller (multicluster-operators-subscription) of Red Hat Advanced Cluster Management for Kubernetes. A user with namespace-scoped edit privileges can create a Channel resource pointing to a controlled Helm repository and a Subscription resource referencing it. The controller applies the Helm chart with its own elevated authority without verifying the subscription-admin role or restricting resources to the subscription namespace, enabling deployment of cluster-scoped resources such as a ClusterRoleBinding granting cluster-admin. Reported by Christopher Lusk of North Echo Security Research. Red Hat states no mitigation meeting their criteria is currently available.

Root causeTechnical detail
https://access.redhat.com/security/cve/CVE-2026-10090
Research notes
  • Root cause
    The Application Subscription controller applies Helm chart contents with elevated authority without verifying the subscription-admin role or restricting resources to the subscription namespace, allowing namespace-scoped edit users to deploy cluster-scoped resources.
    CVE-2026-10090 - Red Hat Customer Portal
  • Technical detail
    Exploitation uses a Channel resource pointing to an attacker-controlled Helm repository and a Subscription resource; the controller then applies cluster-scoped resources such as a ClusterRoleBinding granting cluster-admin.
    CVE-2026-10090 - Red Hat Customer Portal

References

2