{
  "threat_severity" : "Important",
  "public_date" : "2026-04-07T14:00:35Z",
  "bugzilla" : {
    "description" : "rhacm: Open Cluster Management (OCM): Cross-cluster privilege escalation via improper Kubernetes client certificate renewal validation",
    "id" : "2450590",
    "url" : "https://bugzilla.redhat.com/show_bug.cgi?id=2450590"
  },
  "cvss3" : {
    "cvss3_base_score" : "8.2",
    "cvss3_scoring_vector" : "CVSS:3.1/AV:L/AC:L/PR:H/UI:N/S:C/C:H/I:H/A:H",
    "status" : "verified"
  },
  "cwe" : "CWE-295",
  "details" : [ "A flaw was found in Open Cluster Management (OCM), the technology underlying Red Hat Advanced Cluster Management (ACM). Improper validation of Kubernetes client certificate renewal allows a managed cluster administrator to forge a client certificate that can be approved by the OCM controller. This enables cross-cluster privilege escalation and may allow an attacker to gain control over other managed clusters, including the hub cluster.", "A flaw was found in Open Cluster Management (OCM), the technology underlying Red Hat Advanced Cluster Management (ACM). Improper validation of Kubernetes client certificate renewal allows a managed cluster administrator to forge a client certificate that can be approved by the OCM controller. This enables cross-cluster privilege escalation and may allow an attacker to gain control over other managed clusters, including the hub cluster." ],
  "statement" : "Improper validation of Kubernetes client certificate renewal in Open Cluster Management (OCM), the technology underlying Red Hat Advanced Cluster Management (ACM), allows a managed cluster administrator to forge a client certificate. This could lead to cross-cluster privilege escalation, potentially enabling an attacker to gain control over other managed clusters, including the hub cluster.",
  "acknowledgement" : "Red Hat would like to thank Arnaud FEVRIER (Orange) for reporting this issue.",
  "affected_release" : [ {
    "product_name" : "multicluster engine for Kubernetes 2.1",
    "release_date" : "2026-05-04T00:00:00Z",
    "advisory" : "RHSA-2026:13542",
    "cpe" : "cpe:/a:redhat:multicluster_engine:2.10::el9",
    "package" : "multicluster-engine/registration-rhel9:1776881164"
  }, {
    "product_name" : "multicluster engine for Kubernetes 2.11",
    "release_date" : "2026-05-05T00:00:00Z",
    "advisory" : "RHSA-2026:13853",
    "cpe" : "cpe:/a:redhat:multicluster_engine:2.11::el9",
    "package" : "multicluster-engine/registration-rhel9:1777478390"
  }, {
    "product_name" : "multicluster engine for Kubernetes 2.6",
    "release_date" : "2026-04-22T00:00:00Z",
    "advisory" : "RHSA-2026:9848",
    "cpe" : "cpe:/a:redhat:multicluster_engine:2.6::el9",
    "package" : "multicluster-engine/registration-rhel9:1775977180"
  }, {
    "product_name" : "multicluster engine for Kubernetes 2.8",
    "release_date" : "2026-04-15T00:00:00Z",
    "advisory" : "RHSA-2026:8218",
    "cpe" : "cpe:/a:redhat:multicluster_engine:2.8::el9",
    "package" : "multicluster-engine/registration-rhel9:1775638726"
  }, {
    "product_name" : "multicluster engine for Kubernetes 2.9",
    "release_date" : "2026-04-28T00:00:00Z",
    "advisory" : "RHSA-2026:11414",
    "cpe" : "cpe:/a:redhat:multicluster_engine:2.9::el9",
    "package" : "multicluster-engine/registration-rhel9:1776445095"
  } ],
  "package_state" : [ {
    "product_name" : "Multicluster Engine for Kubernetes",
    "fix_state" : "Under investigation",
    "package_name" : "multicluster-engine/addon-manager-rhel9",
    "cpe" : "cpe:/a:redhat:multicluster_engine"
  }, {
    "product_name" : "Multicluster Engine for Kubernetes",
    "fix_state" : "Under investigation",
    "package_name" : "multicluster-engine/maestro-rhel9",
    "cpe" : "cpe:/a:redhat:multicluster_engine"
  }, {
    "product_name" : "Multicluster Engine for Kubernetes",
    "fix_state" : "Under investigation",
    "package_name" : "multicluster-engine/managedcluster-import-controller-rhel9",
    "cpe" : "cpe:/a:redhat:multicluster_engine"
  }, {
    "product_name" : "Multicluster Engine for Kubernetes",
    "fix_state" : "Under investigation",
    "package_name" : "multicluster-engine/placement-rhel9",
    "cpe" : "cpe:/a:redhat:multicluster_engine"
  }, {
    "product_name" : "Multicluster Engine for Kubernetes",
    "fix_state" : "Under investigation",
    "package_name" : "multicluster-engine/registration-operator-rhel9",
    "cpe" : "cpe:/a:redhat:multicluster_engine"
  }, {
    "product_name" : "Multicluster Engine for Kubernetes",
    "fix_state" : "Under investigation",
    "package_name" : "multicluster-engine/work-rhel9",
    "cpe" : "cpe:/a:redhat:multicluster_engine"
  } ],
  "references" : [ "https://www.cve.org/CVERecord?id=CVE-2026-4740\nhttps://nvd.nist.gov/vuln/detail/CVE-2026-4740\nhttps://blog.arfevrier.fr/open-cluster-management-cross-cluster-escape/" ],
  "name" : "CVE-2026-4740",
  "mitigation" : {
    "value" : "Mitigation for this issue is either not available or the currently available options do not meet the Red Hat Product Security criteria comprising ease of use and deployment, applicability to widespread installation base, or stability.",
    "lang" : "en:us"
  },
  "csaw" : false
}