CVE-2026-4740 (GCVE-0-2026-4740)

Vulnerability from cvelistv5 – Published: 2026-04-07 14:30 – Updated: 2026-08-12 12:04
VLAI
Title
Rhacm: open cluster management (ocm): cross-cluster privilege escalation via improper kubernetes client certificate renewal validation
Summary
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
SSVC
Exploitation: none Automatable: no Technical Impact: total
CISA Coordinator · CISA-ADP (v2.0.3)
Decision recorded 2026-04-09 14:40 UTC
CWE
  • CWE-295 - Improper Certificate Validation
Assigner
References
Impacted products
Vendor Product Version
Red Hat multicluster engine for Kubernetes 2.1 Unaffected: 1776881164 , < * (rpm)
    cpe:/a:redhat:multicluster_engine:2.10::el9
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Red Hat multicluster engine for Kubernetes 2.11 Unaffected: 1777478390 , < * (rpm)
    cpe:/a:redhat:multicluster_engine:2.11::el9
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Red Hat multicluster engine for Kubernetes 2.6 Unaffected: 1775977180 , < * (rpm)
    cpe:/a:redhat:multicluster_engine:2.6::el9
 Create a notification for this product.
Red Hat multicluster engine for Kubernetes 2.8 Unaffected: 1775638726 , < * (rpm)
    cpe:/a:redhat:multicluster_engine:2.8::el9
 Create a notification for this product.
Red Hat multicluster engine for Kubernetes 2.9 Unaffected: 1776445095 , < * (rpm)
    cpe:/a:redhat:multicluster_engine:2.9::el9
 Create a notification for this product.
Red Hat Multicluster Engine for Kubernetes     cpe:/a:redhat:multicluster_engine
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Date Public
2026-04-07 14:00
Credits
Red Hat would like to thank Arnaud FEVRIER (Orange) for reporting this issue.
Show details on NVD website
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      "cveMetadata": "{\"cveId\": \"CVE-2026-4740\", \"state\": \"PUBLISHED\", \"dateUpdated\": \"2026-08-12T12:04:56.851Z\", \"dateReserved\": \"2026-03-24T03:19:46.998Z\", \"assignerOrgId\": \"53f830b8-0a3f-465b-8143-3b8a9948e749\", \"datePublished\": \"2026-04-07T14:30:36.396Z\", \"assignerShortName\": \"redhat\"}",
      "dataType": "CVE_RECORD",
      "dataVersion": "5.2"
    }
  }
}



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Taxonomy of the tags.





Forecast uses a logistic model when the trend is rising, or an exponential decay model when the trend is falling. Fitted via linearized least squares.

Sightings

Author Source Type Date Other

Nomenclature

  • Seen: The vulnerability was mentioned, discussed, or observed by the user.
  • Confirmed: The vulnerability has been validated from an analyst's perspective.
  • Published Proof of Concept: A public proof of concept is available for this vulnerability.
  • Exploited: The vulnerability was observed as exploited by the user who reported the sighting.
  • Patched: The vulnerability was observed as successfully patched by the user who reported the sighting.
  • Not exploited: The vulnerability was not observed as exploited by the user who reported the sighting.
  • Not confirmed: The user expressed doubt about the validity of the vulnerability.
  • Not patched: The vulnerability was not observed as successfully patched by the user who reported the sighting.


Detection rules are retrieved from Rulezet.