CVE-2026-4740CWE-295

CVE-2026-4740

High · published April 7, 2026

CVSS v3.1
8.2
EPSS
0%
Percentile
5.3
In the wild
Unconfirmed
What it is

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.

The record
Technical detail
CVSS v3.1
8.2 · HIGH
Vector
CVSS:3.1/AV:L/AC:L/PR:H/UI:N/S:C/C:H/I:H/A:H
CVSS v4.0
Not supplied
EPSS
0.00164 · 5.3th percentile
Weakness
CWE-295 · Improper Certificate Validation
Published
2026-04-07T19:17Z
Affected products (1)
ProductVersionsFixed in
redhat/advanced_cluster_management_for_kubernetesall versions—
References (16)
https://access.redhat.com/errata/RHSA-2026:11414 · [email protected]https://access.redhat.com/errata/RHSA-2026:13542 · [email protected]https://access.redhat.com/errata/RHSA-2026:13853 · [email protected]https://access.redhat.com/errata/RHSA-2026:8218 · [email protected]https://access.redhat.com/errata/RHSA-2026:9848 · [email protected]https://access.redhat.com/security/cve/CVE-2026-4740 · [email protected]https://blog.arfevrier.fr/open-cluster-management-cross-cluster-escape/ · [email protected]https://bugzilla.redhat.com/show_bug.cgi?id=2450590 · [email protected]https://access.redhat.com/errata/RHSA-2026:11414 · 0b0ca135-0b70-47e7-9f44-1890c2a1c46chttps://access.redhat.com/errata/RHSA-2026:13542 · 0b0ca135-0b70-47e7-9f44-1890c2a1c46chttps://access.redhat.com/errata/RHSA-2026:13853 · 0b0ca135-0b70-47e7-9f44-1890c2a1c46chttps://access.redhat.com/errata/RHSA-2026:8218 · 0b0ca135-0b70-47e7-9f44-1890c2a1c46chttps://access.redhat.com/errata/RHSA-2026:9848 · 0b0ca135-0b70-47e7-9f44-1890c2a1c46chttps://access.redhat.com/security/cve/CVE-2026-4740 · 0b0ca135-0b70-47e7-9f44-1890c2a1c46chttps://bugzilla.redhat.com/show_bug.cgi?id=2450590 · 0b0ca135-0b70-47e7-9f44-1890c2a1c46chttps://security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-4740.json · 0b0ca135-0b70-47e7-9f44-1890c2a1c46c
EPSS history
Timeline
  • 07 APR 14:30Z
    Rhacm: open cluster management (ocm): cross-cluster privilege escalation via improper kubernetes client certificate renewal validation
    cvelistv5