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Full vulnerability report · 2026
CVE-2026-10090High confidence

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

Red Hat · Red Hat Advanced Cluster Management for Kubernetes 2.11

9.0CriticalCVSS 3.1
Recommended action
Within 7 days

Critical technical severity; prioritise exposed affected systems while verifying vendor guidance.

Patch available
Direct vendor intelligence

Authoritative vendor CSAF and VEX advisories

Structured product status and remediation from the issuing vendor. Product-state explanations are always visible; large lists can be searched or downloaded.

1 current
CVE-2026-10090 · CSAF 2.0 · revision 3 · finalRed Hat Product Securitymulticluster-operators-subscription: multicluster-operators-subscription: namespace edit user can deploy cluster-scoped ClusterRoleBinding and become cluster-admin via Application Subscription
24 fixed

The vendor explicitly identifies these products or versions as containing the fix.

  • registry.redhat.io/rhacm2/multicluster-operators-subscription-rhel9@sha256:34651d8005c0407444a36f6c30d6a2eaff0e6de9343e50eceabb1ba6e3e71d71_amd64 as a component of Red Hat Advanced Cluster Management for Kubernetes 2.11
  • registry.redhat.io/rhacm2/multicluster-operators-subscription-rhel9@sha256:7130706447b1530f9bfde9d8ce3f44144b7ce2936a76c3b536838ec7a9151010_arm64 as a component of Red Hat Advanced Cluster Management for Kubernetes 2.11
  • registry.redhat.io/rhacm2/multicluster-operators-subscription-rhel9@sha256:9981b3d7cf1ce5bca251044e1e4bdc7aa0c36187d3afcff3090f77338b2d42a1_ppc64le as a component of Red Hat Advanced Cluster Management for Kubernetes 2.11
  • registry.redhat.io/rhacm2/multicluster-operators-subscription-rhel9@sha256:fdcd78a10d394fa844c443f77192fc70038c74c9ad6c0855fdbe1791c4e24cb1_s390x as a component of Red Hat Advanced Cluster Management for Kubernetes 2.11
  • registry.redhat.io/rhacm2/multicluster-operators-subscription-rhel9@sha256:001e8b921bdc6229be7b954c79609921545e7227f0588620fa5119c0c092b75c_arm64 as a component of Red Hat Advanced Cluster Management for Kubernetes 2.13
  • registry.redhat.io/rhacm2/multicluster-operators-subscription-rhel9@sha256:7ec13a6f2b21f85d284d14783ace3ceded93f322577d7c0e1dc0384e42c7a844_amd64 as a component of Red Hat Advanced Cluster Management for Kubernetes 2.13
  • registry.redhat.io/rhacm2/multicluster-operators-subscription-rhel9@sha256:b677c50b011d9ad2551e2bf00ec67a22a78e465f8cfccdfd001527e97ffc2a77_ppc64le as a component of Red Hat Advanced Cluster Management for Kubernetes 2.13
  • registry.redhat.io/rhacm2/multicluster-operators-subscription-rhel9@sha256:dd16c51dae5d2efd3ff2e29f81e3b7ae3f3f28a17e684ae888a83f5469307b06_s390x as a component of Red Hat Advanced Cluster Management for Kubernetes 2.13
  • registry.redhat.io/rhacm2/multicluster-operators-subscription-rhel9@sha256:4341ce0bc756c33bb1035dd63f907b9f60557d97ff8a76d53842b668845a6e84_amd64 as a component of Red Hat Advanced Cluster Management for Kubernetes 2.14
  • registry.redhat.io/rhacm2/multicluster-operators-subscription-rhel9@sha256:9246d7ed264daf4cb915224d27acd5cc4c11c64dab119cdd9830bcc7bdaedbc1_arm64 as a component of Red Hat Advanced Cluster Management for Kubernetes 2.14
  • registry.redhat.io/rhacm2/multicluster-operators-subscription-rhel9@sha256:9e45059a2c2b1ced8c089294a8191021472ab93bb726033c18fe5a0a4caa5a6d_ppc64le as a component of Red Hat Advanced Cluster Management for Kubernetes 2.14
  • registry.redhat.io/rhacm2/multicluster-operators-subscription-rhel9@sha256:afaeae9b62e211ffbafc0c271c313bf5119f62d2b8f8c8ba515e4de075011e22_s390x as a component of Red Hat Advanced Cluster Management for Kubernetes 2.14
Summary
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.
Remediation
Before you apply this update, make sure all previously released errata that are relevant to your system are applied. For details on how to apply this update, refer to: https://access.redhat.com/articles/11258
Optional official sources

National CERT insights
?CERT means Computer Emergency Response Team; CSIRT is the closely related term Computer Security Incident Response Team.

Select the national-authority views to include. The exact source language is shown on each matched advisory. Your choice is remembered on this device and encoded in the shareable URL.

Official European source

ENISA European Vulnerability Database

Official EUVD identifiers, advisory evidence and known-exploited context. Missing fields are not treated as evidence of low risk.

1 current
ENISA EUVD identifier

EUVD-2026-53294

No EUVD known-exploited evidence

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.

EUVD state
Present in the current official mapping
Known exploitation
Not present in the current ENISA EUVD known-exploited dataset. This is not proof of no exploitation.
ENISA score
9.0 · CVSS 3.1
Advisory evidence
No linked advisory details stored yet
Recommended actionWithin 7 days

Critical technical severity; prioritise exposed affected systems while verifying vendor guidance.

Patch available
01

What, why and how

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.

What

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.

Why

A particular privilege, role, capability, or right can be used to perform unsafe actions that were not intended, even when it is assigned to the correct entity.

How

An attacker operating through a network path may attempt exploitation with elevated privileges. If successful, the issue may gain additional privileges.

What

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.

Why

A particular privilege, role, capability, or right can be used to perform unsafe actions that were not intended, even when it is assigned to the correct entity.

How

An attacker operating through a network path may attempt exploitation with elevated privileges. If successful, the issue may gain additional privileges.

02

Exploit reality and attack path

CVSS severity, EPSS forecast probability, public exploit material and CISA-confirmed exploitation are separate signals.

Observed exploitation
?Confirmed exploitation and public exploit material are separate signals. Attacks can occur without public proof-of-concept or exploit code.
No confirmed evidence

No CISA KEV match was present at the last successful refresh. This means no confirmation from that source, not proof of no exploitation.

Public PoC / exploit material
?Confirmed exploitation and public exploit material are separate signals. Attacks can occur without public proof-of-concept or exploit code.
None recorded

No exploit-tagged reference or CISA SSVC proof-of-concept state is currently recorded. Research may still exist outside the structured feeds.

Likely attack path
a network path → Privilege Defined With Unsafe Actions → gain additional privileges
Attack surface
Network
Privileges required
High: elevated access is required
User interaction
None
Attack complexity
Low: no specialised conditions are recorded
Security boundary
Changed: exploitation can affect a different security authority
Weakness
?CWE means Common Weakness Enumeration: a standard category for the underlying weakness.
CWE-267 ↗

CWE-267: Privilege Defined With Unsafe Actions. A particular privilege, role, capability, or right can be used to perform unsafe actions that were not intended, even when it is assigned to the correct entity.

CVSS vector
?CVSS means Common Vulnerability Scoring System. The vector records the metric values used to calculate technical severity.
CVSS:3.1/AV:N/AC:L/PR:H/UI:N/S:C/C:H/I:H/A:L

Common Vulnerability Scoring System 3.1: the compact vector below is decoded into plain language.

AVNetworkAttack vector: The vulnerable component can be reached over a network.ACLowAttack complexity: No specialised conditions are required beyond attacker-controlled input.PRHighPrivileges required: The attacker needs elevated or administrative privileges.UINoneUser interaction: No action by another user is required.SChangedScope: The attack can affect a component governed by a different security authority.CHighConfidentiality impact: A successful attack can cause a major loss.IHighIntegrity impact: A successful attack can cause a major loss.ALowAvailability impact: A successful attack can cause a limited loss.
Post-exploitation / living off the land
No specific living-off-the-land technique is confirmed in the structured sources. Monitor normal administration tools for activity inconsistent with the affected service's baseline.
NetworkPrivilege escalationCWE-267
A

Official authority intelligence

Only matched European and national findings are included. Language selectors and unavailable sources are omitted.

ENISA EUVD · EUVD-2026-53294Official EUVD mapping

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.

Official EUVD record ↗
Canadian Centre for Cyber Security · English · AV26-803Red Hat security advisory (AV26-803)

As of August 5, 2026, Red Hat is affected by a vulnerability in the following product:

Official advisory ↗
Cyber Security Agency of Singapore · English · CSA-SB-20260812Security Bulletin 12 Aug 2026

The Cyber Security Agency of Singapore included this CVE in its official Security Bulletin 12 Aug 2026, published on 12 August 2026. Open the linked bulletin for the product, severity and reference information published in that issue.

Official advisory ↗
03

Patch and workaround

Operational remediation based on structured source evidence.

Status
?Patch availability is based on structured fixed-version fields and authoritative update references. If no fix is verified, check the vendor advisory before making a change.
Patch available
Affected
Fixed
Action
Before you apply this update, make sure all previously released errata that are relevant to your system are applied. For details on how to apply this update, refer to: https://access.redhat.com/articles/11258
Workaround
No verified workaround is recorded. If business-safe, reduce exposure to the affected interface and allow only trusted sources until authoritative guidance is available.
04

Evidence and provenance

Published 5 Aug 2026 · Last source change 27 Aug 2026, 02:17 UTC · CWE-267 · Privilege Defined With Unsafe Actions

CVE recordCVE.org · 5.2
CVSS sourceCNA
EPSS source
?The date BlackTree first stored a score for this CVE from the daily FIRST EPSS feed.
FIRST · tracked since 2026-08-14
European sourceENISA EUVD · EUVD-2026-53294
Product sourceCNA
Remediation sourceVendor CSAF · Red Hat Product Security
CWE sourceCNA
NVD statusNVD awaiting enrichment

Missing structured fields: affected versions. Missing data is not evidence of low risk; review the primary advisory.

Material change intelligence

What changed after publication

View recent updates ↗
  1. Affected versionsThe structured affected or fixed version information changed.
    Before
    See the vendor and CVE records for the affected range. · Fixed: 1787263584 < *; 1787263693 < *; 1787170830 < *; 1787240030 < *; 1787242321 < *; 1787242108 < *
    After
    See the vendor and CVE records for the affected range. · Fixed: Red Hat Advanced Cluster Management for Kubernetes 2.11: 1787263584 < *; Red Hat Advanced Cluster Management for Kubernetes 2.13: 1787263693 < *; Red Hat Advanced Cluster Management for Kubernetes 2.14: 1787170830 < *; Red Hat Advanced Cluster Management for Kubernetes 2.15: 1787240030 < *; Red Hat Advanced Cluster Management for Kubernetes 2.16: 1787242321 < *; Red Hat Advanced Cluster Management for Kubernetes 2.17: 1787242108 < *
    CNA ↗
  2. Affected versionsThe structured affected or fixed version information changed.
    Before
    See the vendor and CVE records for the affected range. · Fixed: 1787263693 < *; 1787240030 < *; 1787242108 < *
    After
    See the vendor and CVE records for the affected range. · Fixed: 1787263584 < *; 1787263693 < *; 1787170830 < *; 1787240030 < *; 1787242321 < *; 1787242108 < *
    CNA ↗
  3. Vendor guidanceAuthoritative vendor guidance changed from no authoritative guidance recorded to authoritative remediation link.
    Before
    no authoritative guidance recorded
    After
    authoritative remediation link
    CNA ↗
  4. Affected versionsThe structured affected or fixed version information changed.
    Before
    See the vendor and CVE records for the affected range. · Fixed: No fixed version is explicitly recorded in the structured CVE data.
    After
    See the vendor and CVE records for the affected range. · Fixed: 1787263693 < *; 1787240030 < *; 1787242108 < *
    CNA ↗
  5. Remediation statusRemediation status changed from Awaiting fix to Patch available.
    Before
    Awaiting fix
    After
    Patch available
    CNA ↗
Material fields only · duplicate refreshes suppressed · history retained for the configured operational retention period
CVE published
Fixed release or patch reference recorded
ENISA EUVD · EUVD-2026-53294↗Vendor CSAF · Red Hat Product Security↗CVE authority or vendor reference↗Official CVE record (CNA and ADP data)↗NVD record↗
Technical terms and abbreviations used in this report
CVE
Common Vulnerabilities and Exposures: the public identifier for one disclosed vulnerability.
CVSS
Common Vulnerability Scoring System: a technical severity framework; it is not patching priority by itself.
EPSS
Exploit Prediction Scoring System: FIRST's estimate of the probability that exploitation activity will be observed in the next 30 days; it is a forecast, not confirmation.
CWE
Common Weakness Enumeration: the standard category describing the underlying software or hardware weakness.
CNA
CVE Numbering Authority: an organisation authorised to assign and publish CVE records.
CISA ADP
Cybersecurity and Infrastructure Security Agency Authorized Data Publisher: structured enrichment added to a CVE record.
NVD
National Vulnerability Database: NIST's enrichment service for CVE records.
CERT / CSIRT
A computer security incident response team that publishes warnings or coordinates incident response.
PoC
Proof of concept: public material that demonstrates or helps reproduce exploitation.
CSAF
Common Security Advisory Framework: a machine-readable format for security advisories.
LoTL
Living off the land: abuse of legitimate tools or system functions during an attack.
Free version - for non-commercial use only.CVE-2026-10090 · cve.blacktree.nl