Security readout for executives and security teams
Plain-English summary
An administrator of one managed Kubernetes cluster could abuse certificate renewal trust to gain privileges across other clusters, potentially including the central hub. A successful compromise could expose workloads, data, and cluster administration across the managed environment.
Executive priority
Prioritize remediation for environments where multiple sensitive clusters share an OCM or ACM hub. The prerequisite limits opportunistic attacks, but compromise of any managed-cluster administrator could expand into an estate-wide control event.
Technical view
OCM improperly validates Kubernetes client certificate renewals. A highly privileged managed-cluster user can forge a client certificate that the OCM controller may approve, enabling cross-cluster privilege escalation. The CVSS 3.1 score is 8.2 with changed scope and high confidentiality, integrity, and availability impacts.
Likely exposure
Exposure concerns Red Hat Multicluster Engine registration components in listed 2.6, 2.8, 2.9, 2.10, and 2.11 product lines. The bundle contains ambiguous version identifiers and marks several related packages unknown, so confirm exact affected builds with Red Hat.
Exploitation context
Exploitation requires high existing privileges on a managed cluster and no user interaction. The resulting access may cross security boundaries into peer clusters or the hub. The bundle states KEV is false and provides no evidence of active exploitation.
Researcher notes
CWE-295 describes the certificate-validation weakness. Assessment should focus on renewal authorization, identity-to-cluster binding, and controller approval behavior. Avoid assuming every Multicluster Engine component is affected; the bundle explicitly leaves several package statuses unknown.
Mitigation direction
- Review each listed Red Hat advisory for the update applicable to your deployed Multicluster Engine version.
- Apply vendor-provided updates to affected registration components under normal change controls.
- Restrict managed-cluster administrative privileges to essential personnel and service identities.
- Monitor Red Hat guidance for components whose affected status remains unknown.
Validation and detection
- Inventory Multicluster Engine versions and registration package builds across hub and managed clusters.
- Compare installed builds with the applicability and fixed-build information in the relevant Red Hat advisory.
- Review certificate renewal and approval records for unexpected identities, subjects, or managed-cluster associations.
- Audit recent hub and cross-cluster administrative activity originating from managed-cluster identities.
Public sources used
Generated from the cited source records. This long-tail analysis has not been individually reviewed by a named human.
Conservative CVE-to-ATT&CK context
These mappings and lookup hints may be relevant to the vulnerability behavior, CWE, affected product, or exposure path. Glexia-inferred context is not an official MITRE, ATT&CK, CWE, or CVE Program mapping.
ATT&CK lookup starting points
Use these exact CWE pages and searches to review the Glexia ATT&CK library from this CVE's weakness and description context.
CWE-295: Exact CWE lookup
Use the exact CWE identifier as the starting point before reviewing related ATT&CK behavior. Open the exact CWE lookup page first, then review the ATT&CK searches from that MITRE weakness context. This is a Glexia lookup hint, not an official ATT&CK mapping.
Open ATT&CK lookupPrivilege behavior lookup
The CVE wording references privilege impact, so privilege escalation and authorization behavior review may help. This is a Glexia inferred lookup path, not an official MITRE, ATT&CK, or CVE Program mapping.
Open ATT&CK lookupContainer behavior lookup
The affected technology mentions containers, so container-specific ATT&CK technique review may help. This is a Glexia inferred lookup path, not an official MITRE, ATT&CK, or CVE Program mapping.
Open ATT&CK lookupCVE-2026-4740 mapping review
Open the CVE-to-ATT&CK bridge for reviewed, inferred, or future official mappings tied to this CVE.
Open ATT&CK lookup- Severity
- High
- CVSS
- 8.2 (3.1)
- Known Exploited
- No
- Published
Vector: CVSS:3.1/AV:L/AC:L/PR:H/UI:N/S:C/C:H/I:H/A:H
CNA and ADP enrichment extracted from CVE v5
These fields come from the CVE record and ADP containers, not from Glexia's Take. They preserve time-varying source decisions such as CISA SSVC, KEV status, CVSS metrics, and provider references.
SSVC decision data
CVSS vector scores
2 official scoresWe collect every scored CVSS vector available in the official CNA and ADP containers. When more than one version is present, the table keeps the source vectors side by side instead of collapsing them into the highest score.
CVSS:3.1/AV:L/AC:L/PR:H/UI:N/S:C/C:H/I:H/A:H1.56redhatCVSS:3.1/AV:L/AC:L/PR:H/UI:N/S:C/C:H/I:H/A:H1.56redhat-SADPVulnerability scoring details
Base CVSS 3.1 score
8.2HighVector: CVSS:3.1/AV:L/AC:L/PR:H/UI:N/S:C/C:H/I:H/A:H
Base CVSS 3.1 score
8.2HighVector: CVSS:3.1/AV:L/AC:L/PR:H/UI:N/S:C/C:H/I:H/A:H
Vulnerability timeline
Timeline events are normalized from CVE metadata, CNA source timelines, ADP timelines, and KEV metadata when present.
- ADP timelineredhat-SADP
Reported to Red Hat.
- Source timelineredhat
Reported to Red Hat.
- CVE reservedCVE Program
The CVE ID was reserved by the assigning CNA.
- ADP timelineredhat-SADP
Made public.
- Source timelineredhat
Made public.
- CVE publishedCVE Program
The CVE record was published.
- CVE updatedCVE Program
The CVE record metadata indicates this as the latest update time.
ADP provider summaries
- 2026-03-24T03:18:24.150Z: Reported to Red Hat.
- 2026-04-07T14:00:35.240Z: Made public.
Source materials
- CVE List V5 sourceCVE List V5
- RHSA-2026:11414CVE reference, redhat · vendor-advisory, x_refsource_REDHAT
- RHSA-2026:13542CVE reference, redhat · vendor-advisory, x_refsource_REDHAT
- RHSA-2026:13853CVE reference, redhat · vendor-advisory, x_refsource_REDHAT
- RHSA-2026:8218CVE reference, redhat · vendor-advisory, x_refsource_REDHAT
- RHSA-2026:9848CVE reference, redhat · vendor-advisory, x_refsource_REDHAT
- https://access.redhat.com/security/cve/CVE-2026-4740CVE reference, redhat · vdb-entry, x_refsource_REDHAT
- https://blog.arfevrier.fr/open-cluster-management-cross-cluster-escape/CVE reference, redhat
- RHBZ#2450590CVE reference, redhat · issue-tracking, x_refsource_REDHAT
- https://security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-4740.jsonCVE reference, redhat-SADP · x_sadp-csaf-vex
Products and packages named in the record
CWE details
CWE links open Glexia weakness intelligence pages with official CWE context, developer remediation guidance, and related CVE mappings.
Improper Certificate Validation
Improper Certificate Validation represents a recurring weakness pattern that can create exploitable paths when design, validation, or implementation controls are missing.