Multicluster-operators-subscription: multicluster-operators-subscription: namespace edit user can deploy cluster-scoped clusterrolebinding and become cluster-admin via application subscription
Summary
| CVE | CVE-2026-10090 |
|---|---|
| State | PUBLISHED |
| Assigner | redhat |
| Source Priority | CVE Program / NVD first with legacy fallback |
| Published | 2026-08-05 09:18:14 UTC |
| Updated | 2026-08-12 22:17:13 UTC |
| 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. |
Risk And Classification
Primary CVSS: v3.1 9 CRITICAL from [email protected]
CVSS:3.1/AV:N/AC:L/PR:H/UI:N/S:C/C:H/I:H/A:L
EPSS: 0.002470000 probability, percentile 0.161360000 (date 2026-08-14)
Problem Types: CWE-267 | CWE-267 Privilege Defined With Unsafe Actions
| Version | Source | Type | Score | Severity | Vector |
|---|---|---|---|---|---|
| 3.1 | [email protected] | Primary | 9 | CRITICAL | CVSS:3.1/AV:N/AC:L/PR:H/UI:N/S:C/C:H/I:H/A:L |
| 3.1 | CNA | CVSS | 9 | CRITICAL | CVSS:3.1/AV:N/AC:L/PR:H/UI:N/S:C/C:H/I:H/A:L |
CVSS v3.1 Breakdown
CVSS:3.1/AV:N/AC:L/PR:H/UI:N/S:C/C:H/I:H/A:L
Vendor Declared Affected Products
| Source | Vendor | Product | Version | Platforms |
|---|---|---|---|---|
| CNA | Red Hat | Red Hat Advanced Cluster Management For Kubernetes 2 | Not specified | Not specified |
References
| Reference | Source | Link | Tags |
|---|---|---|---|
| bugzilla.redhat.com/show_bug.cgi | [email protected] | bugzilla.redhat.com | |
| access.redhat.com/security/cve/CVE-2026-10090 | [email protected] | access.redhat.com | |
| CVE Program record | CVE.ORG | www.cve.org | canonical |
| NVD vulnerability detail | NVD | nvd.nist.gov | canonical, analysis |
Vendor Comments And Credit
Discovery Credit
CNA: Red Hat would like to thank Christopher Lusk (North Echo Security Research) for reporting this issue. (en)
Additional Advisory Data
| Source | Time | Event |
|---|---|---|
| CNA | 2026-05-06T00:00:00.000Z | Reported to Red Hat. |
| CNA | 2026-08-05T08:35:00.000Z | Made public. |
Workarounds
CNA: Remove the RBAC aggregation (immediate, targeted) Delete the ClusterRole that aggregates Application Subscription management permissions into the Kubernetes edit role: oc delete clusterrole open-cluster-management:multicloud-operators-subscription:rbac-aggregate-edit Verification: oc auth can-i create subscriptions.apps.open-cluster-management.io --as=<user> -n <namespace> Expected result after mitigation: no Important notes: This ClusterRole is recreated by the multiclusterhub-operator during reconciliation. Customers must re-apply this mitigation after any ACM operator upgrade, operator pod restart, or MultiClusterHub CR modification until a fixed release is installed. After deletion, users with only the edit or view roles will no longer be able to create or delete Application Subscription, Channel, or related resources. Users who are bound to open-cluster-management:subscription-admin or who have explicit RBAC grants are unaffected. Existing Application Subscriptions continue to function normally.