CVE-2026-4740

Rhacm: open cluster management (ocm): cross-cluster privilege escalation via improper kubernetes client certificate renewal validation

HIGH
8.2
CVSS Score
Published: April 7, 2026 at 02:30 PM UTC
Updated: October 26, 2026 at 09:10 PM UTC
1 product affected across 1 vendorAdvanced Cluster Management for Kubernetes

Using Multicluster Engine for Kubernetes by Red Hat?

Get instant alerts when new vulnerabilities affect Multicluster Engine for Kubernetes - before attackers find them.

Real-time alertsTrack your software stackFree plan available
Severity
HIGH8.2
Exploit prediction
EPSS 0.1%
SSVC
No known exploit

Description

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.

Affected

Our own answer: ranges merged, affected separated from platform-only, with confidence and review flags.

References (9)

VDB Entryx_refsource_REDHATVendor Advisory
Source: cverecord
https://access.redhat.com/security/cve/CVE-2026-4740
Issue Trackingx_refsource_REDHATVendor Advisory
Source: cverecord
https://bugzilla.redhat.com/show_bug.cgi?id=2450590
Vendor Advisoryx_refsource_REDHAT
Source: cverecord
https://access.redhat.com/errata/RHSA-2026:11414
Vendor Advisoryx_refsource_REDHAT
Source: cverecord
https://access.redhat.com/errata/RHSA-2026:13853
Vendor Advisoryx_refsource_REDHAT
Source: cverecord
https://access.redhat.com/errata/RHSA-2026:9848
Vendor Advisoryx_refsource_REDHAT
Source: cverecord
https://access.redhat.com/errata/RHSA-2026:13542

SSVC — Action Prioritization

SSVCNo known exploitNot automatableTotal impact

SSVC signals action urgency (what to patch first), separate from CVSS which measures severity.

CVSS

8.2HIGHredhat
Attack Vector
LOCAL
Complexity
LOW
Privileges
HIGH
User Interaction
NONE
Scope
CHANGED
Confidentiality
HIGH
Integrity
HIGH
Availability
HIGH
Vector?

Quick Info

StatusMODIFIED
CWE
CWE-295

Get alerted

Stop reading CVE feeds looking for your own stack

Track the products you run and VulnTracker tells you when a new CVE affects them — with what is known about fixing it, and nothing about the rest.

Free plan, no card