Is CVE-2026-4740 in the CISA KEV catalog?

No. CVE-2026-4740 is not currently on the CISA Known Exploited Vulnerabilities list.

What is the CVSS severity of CVE-2026-4740?

CVE-2026-4740 has a CVSS v3 base score of 8.2 (HIGH).

What is the EPSS score for CVE-2026-4740?

CVE-2026-4740 has an EPSS score of 0.11% (2th percentile), estimating the probability of exploitation in the next 30 days.

How do I fix or mitigate CVE-2026-4740?

No published fix for CVE-2026-4740 has been found yet. Check the linked vendor advisories for guidance as it becomes available.

CVE & CISA-KEV Catalog

CVE-2026-4740

HIGH

8.2

CVSS v3

NVD

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.

CWE-295Improper Certificate Validation

How to fix

No published remediation has been found for this vulnerability's affected products yet.

Mitigation guidance may be in the linked vendor advisories in the References section below.

CVSS v3 Vector

Exploitability

Attack VectorLocal

Attack ComplexityLow

Privileges RequiredHigh

User InteractionNone

ScopeChanged

Impact

ConfidentialityHigh

IntegrityHigh

AvailabilityHigh

CVSS:3.1/AV:L/AC:L/PR:H/UI:N/S:C/C:H/I:H/A:H

Exploit Intelligence

0.11%probability of exploitation in 30 days

2ndpercentile

Low risk: more likely to be exploited than 2% of all known CVEs.

References

Exploit1

blog.arfevrier.fr

Vendor Advisory2

Other references1

security.access.redhat.com

Related Vulnerabilities

Other CWE-295 (Improper Certificate Validation) vulnerabilities, ordered by exploit likelihood. View all

CVE	Severity	CVSS	EPSS	Exploited	Fix
CVE-2015-4000	Low	3.7	100%	-	Fix
CVE-2020-0601	High	8.1	89%	KEV	Fix
CVE-2009-3555	Critical	9.8	87%	-	Fix
CVE-2022-26923	High	8.8	83%	KEV	Fix
CVE-2023-27823	Critical	9.8	53%	-	-
CVE-2022-42979	High	8.8	24%	-	-

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This product uses NVD data but is not endorsed or certified by the NVD. EPSS scores courtesy of FIRST.org (https://www.first.org/epss). Source: CISA KEV Catalog. Data as of 2026-06-30.