GHSA-Q4GV-PJMH-C735

Vulnerability from github – Published: 2026-04-07 15:30 – Updated: 2026-04-08 19:13
VLAI
Summary
Open Cluster Management (OCM): Cross-cluster privilege escalation via improper Kubernetes client certificate renewal validation
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.

Severity
8.2 (High)
CVSS:3.1/AV:L/AC:L/PR:H/UI:N/S:C/C:H/I:H/A:H
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{
  "affected": [
    {
      "package": {
        "ecosystem": "Go",
        "name": "open-cluster-management.io/ocm"
      },
      "ranges": [
        {
          "events": [
            {
              "introduced": "0"
            },
            {
              "fixed": "1.2.1"
            }
          ],
          "type": "ECOSYSTEM"
        }
      ]
    }
  ],
  "aliases": [
    "CVE-2026-4740"
  ],
  "database_specific": {
    "cwe_ids": [
      "CWE-295"
    ],
    "github_reviewed": true,
    "github_reviewed_at": "2026-04-08T19:13:58Z",
    "nvd_published_at": "2026-04-07T15:17:46Z",
    "severity": "HIGH"
  },
  "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.",
  "id": "GHSA-q4gv-pjmh-c735",
  "modified": "2026-04-08T19:13:58Z",
  "published": "2026-04-07T15:30:52Z",
  "references": [
    {
      "type": "ADVISORY",
      "url": "https://nvd.nist.gov/vuln/detail/CVE-2026-4740"
    },
    {
      "type": "WEB",
      "url": "https://github.com/open-cluster-management-io/ocm/commit/9e70cc1e21a15239c81111062c0b37df4b5a8026"
    },
    {
      "type": "WEB",
      "url": "https://access.redhat.com/security/cve/CVE-2026-4740"
    },
    {
      "type": "WEB",
      "url": "https://blog.arfevrier.fr/open-cluster-management-cross-cluster-escape"
    },
    {
      "type": "WEB",
      "url": "https://bugzilla.redhat.com/show_bug.cgi?id=2450590"
    },
    {
      "type": "PACKAGE",
      "url": "https://github.com/open-cluster-management-io/OCM"
    }
  ],
  "schema_version": "1.4.0",
  "severity": [
    {
      "score": "CVSS:3.1/AV:L/AC:L/PR:H/UI:N/S:C/C:H/I:H/A:H",
      "type": "CVSS_V3"
    }
  ],
  "summary": "Open Cluster Management (OCM): Cross-cluster privilege escalation via improper Kubernetes client certificate renewal validation"
}



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