CVE-2026-4740
Rhacm: open cluster management (ocm): cross-cluster privilege escalation via improper kubernetes client certificate renewal validation
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.
INFO
Published Date :
April 7, 2026, 3:17 p.m.
Last Modified :
April 7, 2026, 3:17 p.m.
Remotely Exploit :
No
Source :
[email protected]
Affected Products
The following products are affected by CVE-2026-4740
vulnerability.
Even if cvefeed.io is aware of the exact versions of the
products
that
are
affected, the information is not represented in the table below.
No affected product recoded yet
CVSS Scores
| Score | Version | Severity | Vector | Exploitability Score | Impact Score | Source |
|---|---|---|---|---|---|---|
| CVSS 3.1 | HIGH | [email protected] |
Solution
- Update Open Cluster Management to the latest version.
- Apply Red Hat ACM security updates.
- Review and restrict cluster administrator privileges.
- Monitor certificate renewal processes.
References to Advisories, Solutions, and Tools
Here, you will find a curated list of external links that provide in-depth
information, practical solutions, and valuable tools related to
CVE-2026-4740.
| URL | Resource |
|---|---|
| https://access.redhat.com/security/cve/CVE-2026-4740 | |
| https://blog.arfevrier.fr/open-cluster-management-cross-cluster-escape/ | |
| https://bugzilla.redhat.com/show_bug.cgi?id=2450590 |
CWE - Common Weakness Enumeration
While CVE identifies
specific instances of vulnerabilities, CWE categorizes the common flaws or
weaknesses that can lead to vulnerabilities. CVE-2026-4740 is
associated with the following CWEs:
Common Attack Pattern Enumeration and Classification (CAPEC)
Common Attack Pattern Enumeration and Classification
(CAPEC)
stores attack patterns, which are descriptions of the common attributes and
approaches employed by adversaries to exploit the CVE-2026-4740
weaknesses.
We scan GitHub repositories to detect new proof-of-concept exploits. Following list is a collection of public exploits and proof-of-concepts, which have been published on GitHub (sorted by the most recently updated).
Results are limited to the first 15 repositories due to potential performance issues.
The following list is the news that have been mention
CVE-2026-4740 vulnerability anywhere in the article.
The following table lists the changes that have been made to the
CVE-2026-4740 vulnerability over time.
Vulnerability history details can be useful for understanding the evolution of a vulnerability, and for identifying the most recent changes that may impact the vulnerability's severity, exploitability, or other characteristics.
-
New CVE Received by [email protected]
Apr. 07, 2026
Action Type Old Value New Value Added 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. Added CVSS V3.1 AV:L/AC:L/PR:H/UI:N/S:C/C:H/I:H/A:H Added CWE CWE-295 Added Reference https://access.redhat.com/security/cve/CVE-2026-4740 Added Reference https://blog.arfevrier.fr/open-cluster-management-cross-cluster-escape/ Added Reference https://bugzilla.redhat.com/show_bug.cgi?id=2450590