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CVE Record

CVE-2026-10090: Multicluster-operators-subscription: multicluster-operators-subscription: namespace edit user can deploy cluster-scoped clusterrolebinding and become cluster-admin via application subscription

A flaw was found in the Application Subscription controller (multicluster-operators-subscription) of Red Hat Advanced Cluster Management for Kubernetes (ACM). A user with namespace-scoped "edit" privileges in an ACM hub namespace can create a Channel resource pointing to a Helm repository they control and a Subscription resource referencing it. The app-subscription controller fetches and applies the Helm chart contents with its own elevated authority, without verifying whether the subscription creator holds the "open-cluster-management:subscription-admin" role and without restricting applied resources to the subscription namespace. This allows the attacker to include cluster-scoped resources in the Helm chart, such as a ClusterRoleBinding granting the attacker's ServiceAccount the "cluster-admin" ClusterRole. Successful exploitation results in full cluster-admin privilege escalation. This contradicts the ACM documentation which states that non-subscription-admin users should have resources deployed into the subscription namespace only.

CriticalCVSS 9Not KEV-listedUpdated
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Glexia's TakeAutomated analysiscritical

Security readout for executives and security teams

Plain-English summary

A user trusted to edit one ACM hub namespace can abuse the Application Subscription controller to gain administrator control of the entire Kubernetes cluster. The controller may install attacker-controlled Helm content using elevated permissions, crossing the intended namespace boundary. Compromise could expose sensitive data, permit configuration changes, and disrupt workloads.

Executive priority

Treat as an urgent privilege-escalation risk on ACM hub clusters. Immediately identify exposed hubs, reduce namespace editor access, and investigate suspicious subscriptions or administrator bindings. Schedule vendor-supported remediation as soon as Red Hat identifies the applicable fixed release; the supplied evidence does not name one.

Technical view

In Red Hat Advanced Cluster Management for Kubernetes 2, multicluster-operators-subscription does not verify that a Subscription creator has the subscription-admin role or confine deployed resources to the Subscription namespace. A namespace editor can reference a controlled Helm repository, causing the privileged controller to apply cluster-scoped resources and potentially grant cluster-admin privileges. CVSS 3.1 is 9.0.

Likely exposure

Potentially exposed environments are ACM 2 hub clusters running rhacm2/multicluster-operators-subscription-rhel9 where users or service accounts have edit privileges in hub namespaces. The supplied sources do not identify affected version ranges, so package-version exposure cannot be determined from this bundle alone.

Exploitation context

Exploitation requires authenticated, high namespace-level privileges and control of referenced Helm content, but needs no user interaction and can cross into cluster scope. The bundle marks this CVE as absent from KEV and provides no evidence of active exploitation. That absence does not establish that exploitation has never occurred.

Researcher notes

CWE-267 fits the controller's failure to enforce the documented privilege boundary. Scope changes because a namespace-scoped principal can induce a privileged controller to create cluster-scoped objects. Exact affected and fixed versions, patch availability, detection indicators, and exploitation prevalence are not established by the supplied bundle.

Mitigation direction

  • Check Red Hat guidance for affected versions, corrected packages, and supported remediation.
  • Prioritize applying Red Hat's remediation when an applicable update is identified.
  • Temporarily restrict untrusted users from creating or modifying ACM Channel and Subscription resources.
  • Review and reduce edit privileges in ACM hub namespaces, especially for service accounts.
  • Limit subscriptions to trusted, governed Helm repositories where operationally feasible.

Validation and detection

  • Inventory ACM 2 hub clusters and installed multicluster-operators-subscription package versions.
  • Identify users and service accounts holding edit-equivalent access in ACM hub namespaces.
  • Review Channel and Subscription resources for unapproved repositories, owners, or recent changes.
  • Audit controller-created cluster-scoped resources, especially unexpected ClusterRoleBindings granting cluster-admin.
  • After remediation, confirm namespace editors cannot cause subscriptions to create cluster-scoped resources.
Prepared
Confidence
medium
Sources
4

Public sources used

Generated from the cited source records. This long-tail analysis has not been individually reviewed by a named human.

Potential ATT&CK relevance

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

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cwe · low confidence lookup

CWE-267: Exact CWE lookup

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Privilege 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.

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description · low confidence lookup

Container 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.

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CVE-2026-10090 mapping review

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Vulnerability profileCVE Program record
Severity
Critical
CVSS
9 (3.1)
Known Exploited
No
Published

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

Official CVE source material

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.

1CVSS vectors
5Timeline events
1ADP providers
3Source links

SSVC decision data

CISA-ADPCISA Coordinator
Timestamp
Version
2.0.3
Exploitation: noneAutomatable: noTechnical Impact: total

CVSS vector scores

1 official score

We 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.

ScoreVersionSeverityVectorExploitImpactSource
9CVSS 3.1CriticalCVSS:3.1/AV:N/AC:L/PR:H/UI:N/S:C/C:H/I:H/A:L2.36redhat

Vulnerability scoring details

Base CVSS 3.1 score

9Critical
CVSS 3.1 vector shape for CVE-2026-10090Attack VectorAttack ComplexityPrivileges RequiredUser InteractionScopeConfidentiality ImpactIntegrity ImpactAvailability Impact

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

Attack Vector
NetworkAdjacentLocalPhysical
Attack Complexity
LowHigh
Privileges Required
NoneLowHigh
User Interaction
NoneRequired
Scope
ChangedUnchanged
Confidentiality Impact
HighLowNone
Integrity Impact
HighLowNone
Availability Impact
HighLowNone

Vulnerability timeline

Timeline events are normalized from CVE metadata, CNA source timelines, ADP timelines, and KEV metadata when present.

  1. Source timelineredhat

    Reported to Red Hat.

  2. CVE reservedCVE Program

    The CVE ID was reserved by the assigning CNA.

  3. Source timelineredhat

    Made public.

  4. CVE publishedCVE Program

    The CVE record was published.

  5. CVE updatedCVE Program

    The CVE record metadata indicates this as the latest update time.

ADP provider summaries

CISA-ADPCISA ADP Vulnrichment
other:ssvc

Source materials

Affected products

Products and packages named in the record

VendorProductVersion / packageStatus
Red HatRed Hat Advanced Cluster Management for Kubernetes 2rhacm2/multicluster-operators-subscription-rhel9affected
Weakness

CWE details

CWE-267

CWE links open Glexia weakness intelligence pages with official CWE context, developer remediation guidance, and related CVE mappings.

CWE-267 · source CWE mapping

Privilege Defined With Unsafe Actions

Privilege Defined With Unsafe Actions represents a recurring weakness pattern that can create exploitable paths when design, validation, or implementation controls are missing.

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