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Full vulnerability report · 2026
CVE-2026-54100High confidence

Windows-machine-config-operator: windows-machine-config-operator: ssh host key not verified enables credential theft

Red Hat · Red Hat OpenShift for Windows Containers 10.21

Official source article: Red Hat RHSA-2026:47173 ↗. Check the applicable product and release in the original source.

8.3HighCVSS 3.1
Recommended action
Within 7 days

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

Patch available
R
Operational reassessment

Published severity in operational context

Open reassessment dashboard →
Published severityHighOperational priority:High, unchanged from published severity.unchanged

Evidence used

  • No CISA KEV confirmation is currently recorded.
  • EPSS is 0.30% for the current model date.

Compensating controls

  • Validate the affected product branch and deploy the verified fixed release.
  • Restrict local access and enforce least privilege on affected hosts.
  • Monitor vendor guidance and exploitation sources for a material change.

Verification

  1. Confirm that the asset runs Red Hat Red Hat OpenShift for Windows Containers 10.21 and falls inside the recorded affected range.
  2. Verify the installed build against the product-specific fixed version after deployment.
  3. Validate exposure, authentication requirements and compensating controls in the actual environment.
  4. Reopen this reassessment when CVSS, KEV, EPSS, exploit evidence or remediation changes.
Mitigation target: Within 30 daysRemediation target: Within 180 days

This automated reassessment organises public evidence. It does not know asset exposure, business impact or control effectiveness and does not replace CVSS or a human risk decision.

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-2026-54100 · CSAF 2.0 · revision 3 · finalRed Hat Product Securitywindows-machine-config-operator: windows-machine-config-operator: SSH host key not verified enables credential theft
2 known affected

The vendor explicitly identifies these products as affected by this CVE.

  • openshift4-wincw/windows-machine-config-rhel8-operator as a component of Red Hat OpenShift Container Platform 4
  • openshift4-wincw/windows-machine-config-rhel9-operator as a component of Red Hat OpenShift Container Platform 4
Summary
A flaw was found in the Windows Machine Config Operator (WMCO) for Red Hat OpenShift Container Platform. WMCO establishes SSH connections to Windows worker nodes without verifying the remote server host key. An adjacent-network attacker who can intercept or redirect WMCO's SSH session can capture WICD and kubelet bootstrap credentials transferred during node configuration, enabling compromise of Windows node identities in the cluster.
Remediation
For Windows Machine Config Operator upgrades, see the following documentation: https://docs.redhat.com/en/documentation/openshift_container_platform/4.21/html/windows_container_support_for_openshift/windows-node-upgrades
Optional official sources

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

Choose official national sources for this report. Each advisory shows its original language. Your selection is remembered on this device and included in shared links.

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-2026-38234

No EUVD known-exploited evidence

A flaw was found in the Windows Machine Config Operator (WMCO) for Red Hat OpenShift Container Platform. WMCO establishes SSH connections to Windows worker nodes without verifying the remote server host key. An adjacent-network attacker who can intercept or redirect WMCO's SSH session can capture WICD and kubelet bootstrap credentials transferred during node configuration, enabling compromise of Windows node identities in the cluster.

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
8.3 · CVSS 3.1
Advisory evidence
No linked advisory details stored yet
Recommended actionWithin 7 days

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

Patch available
01

What, why and how

A flaw was found in the Windows Machine Config Operator (WMCO) for Red Hat OpenShift Container Platform. WMCO establishes SSH connections to Windows worker nodes without verifying the remote server host key. An adjacent-network attacker who can intercept or redirect WMCO's SSH session can capture WICD and kubelet bootstrap credentials transferred during node configuration, enabling compromise of Windows node identities in the cluster.

What

A flaw was found in the Windows Machine Config Operator (WMCO) for Red Hat OpenShift Container Platform. WMCO establishes SSH connections to Windows worker nodes without verifying the remote server host key. An adjacent-network attacker who can intercept or redirect WMCO's SSH session can capture WICD and kubelet bootstrap credentials transferred during node configuration, enabling compromise of Windows node identities in the cluster.

Why

The product does not validate, or incorrectly validates, a certificate.

How

An attacker operating through an adjacent network may attempt exploitation without authentication or user interaction. If successful, the issue may cause the confidentiality, integrity or availability impact described by the vendor.

What

A flaw was found in the Windows Machine Config Operator (WMCO) for Red Hat OpenShift Container Platform. WMCO establishes SSH connections to Windows worker nodes without verifying the remote server host key. An adjacent-network attacker who can intercept or redirect WMCO's SSH session can capture WICD and kubelet bootstrap credentials transferred during node configuration, enabling compromise of Windows node identities in the cluster.

Why

The product does not validate, or incorrectly validates, a certificate.

How

An attacker operating through an adjacent network may attempt exploitation without authentication or user interaction. If successful, the issue may cause the confidentiality, integrity or availability impact described by the vendor.

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
an adjacent network → Improper Certificate Validation → cause the confidentiality, integrity or availability impact described by the vendor
Attack surface
Adjacent
Privileges required
None: unauthenticated exploitation is possible
User interaction
None
Attack complexity
High: exploitation depends on specific conditions
Security boundary
Changed: exploitation can affect a different security authority
Weakness
?CWE means Common Weakness Enumeration: a standard category for the underlying weakness.
CWE-295 ↗

CWE-295: Improper Certificate Validation. The product does not validate, or incorrectly validates, a certificate.

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

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

AVAdjacentAttack vector: The attacker must be on an adjacent or logically close network.ACHighAttack complexity: Successful exploitation depends on specific conditions outside the attacker's direct control.PRNonePrivileges required: The attacker does not need an account or existing 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.AHighAvailability impact: A successful attack can cause a major loss.
Post-exploitation / living off the land
Stolen credentials, tokens and legitimate administration functions may provide continued access without deploying a large custom toolset.
UnauthenticatedCWE-295
A

Official authority intelligence

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

ENISA EUVD · EUVD-2026-38234Official EUVD mapping

A flaw was found in the Windows Machine Config Operator (WMCO) for Red Hat OpenShift Container Platform. WMCO establishes SSH connections to Windows worker nodes without verifying the remote server host key. An adjacent-network attacker who can intercept or redirect WMCO's SSH session can capture WICD and kubelet bootstrap credentials transferred during node configuration, enabling compromise of Windows node identities in the cluster.

Official EUVD record ↗
BSI · German · WID-SEC-2026-2552Red Hat OpenShift für Windows Containers (WMCO): Mehrere Schwachstellen

Ein Angreifer kann mehrere Schwachstellen in Red Hat OpenShift für Windows Containers ausnutzen, um Administratorrechte zu erlangen und vertrauliche Informationen offenzulegen.

Official advisory ↗
Cyber Security Agency of Singapore · English · CSA-SB-20260624Security Bulletin 24 June 2026

The Cyber Security Agency of Singapore included this CVE in its official Security Bulletin 24 June 2026, published on 24 June 2026. Open the linked bulletin for the product, severity and reference information published in that issue.

Official advisory ↗
JVN iPedia · Japanese · JVNDB-2026-022986レッドハットのRed Hat OpenShift Container Platform等の複数製品における証明書検証に関する脆弱性

Red Hat OpenShift Container Platform向けのWindows Machine Config Operator（WMCO）に脆弱性が発見されました。WMCOはリモートサーバのホストキーを検証せずにWindowsワーカーノードへSSH接続を確立します。隣接ネットワーク上の攻撃者がWMCOのSSHセッションを傍受またはリダイレクトできる場合、ノードの設定中に転送されるWICDおよびkubeletのブートストラップ認証情報を取得でき、クラスター内のWindowsノードの識別情報が侵害される恐れがあります。

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
For Windows Machine Config Operator upgrades, see the following documentation: https://docs.redhat.com/en/documentation/openshift_container_platform/4.21/html/windows_container_support_for_openshift/windows-node-upgrades
Workaround
No verified workaround is recorded. Limit untrusted access and use least privilege until authoritative guidance is available.
04

Evidence and provenance

Published 22 Jun 2026 · Last source change 9 Sept 2026, 12:05 UTC · CWE-295 · Improper Certificate Validation

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-2026-38234
Product sourceVendor CSAF · Red Hat Product Security
Remediation sourceVendor CSAF · Red Hat Product Security
CWE sourceCNA
NVD statusNVD modified after enrichment

Core structured fields are present and their contributing authorities are shown above.

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: Red Hat OpenShift for Windows Containers 10.22: 1783692800 < *
    After
    See the vendor and CVE records for the affected range. · Fixed: Red Hat OpenShift for Windows Containers 10.21: 1787065708 < *; Red Hat OpenShift for Windows Containers 10.22: 1783692800 < *
    CNA ↗
  2. Affected versionsThe structured affected or fixed version information changed.
    Before
    openshift4-wincw/windows-machine-config-rhel8-operator as a component of Red Hat OpenShift Container Platform 4; openshift4-wincw/windows-machine-config-rhel9-operator as a component of Red Hat OpenShift Container Platform 4 · Fixed: registry.redhat.io/openshift4-wincw/windows-machine-config-rhel9-operator@sha256:c5ffbe845d71ab95834ee74201fca1147954d6c3943042720831e06230228d8e_amd64 as a component of OpenShift Windows Machine Config Operator 10.21; registry.redhat.io/openshift4-wincw/windows-machine-config-rhel9-operator@sha256:3aacd9560f3408becf4b3618590a620d72aff0313a5efb23542552a6fd59500f_amd64 as a component of Red Hat OpenShift for Windows Containers 10.22
    After
    openshift4-wincw/windows-machine-config-rhel8-operator as a component of Red Hat OpenShift Container Platform 4; openshift4-wincw/windows-machine-config-rhel9-operator as a component of Red Hat OpenShift Container Platform 4 · Fixed: registry.redhat.io/openshift4-wincw/windows-machine-config-rhel9-operator@sha256:c5ffbe845d71ab95834ee74201fca1147954d6c3943042720831e06230228d8e_amd64 as a component of Red Hat OpenShift for Windows Containers 10.21; registry.redhat.io/openshift4-wincw/windows-machine-config-rhel9-operator@sha256:3aacd9560f3408becf4b3618590a620d72aff0313a5efb23542552a6fd59500f_amd64 as a component of Red Hat OpenShift for Windows Containers 10.22
    Red Hat Product Security ↗
  3. Affected versionsThe structured affected or fixed version information changed.
    Before
    openshift4-wincw/windows-machine-config-rhel8-operator as a component of Red Hat OpenShift Container Platform 4; openshift4-wincw/windows-machine-config-rhel9-operator as a component of Red Hat OpenShift Container Platform 4 · Fixed: registry.redhat.io/openshift4-wincw/windows-machine-config-rhel9-operator@sha256:c5ffbe845d71ab95834ee74201fca1147954d6c3943042720831e06230228d8e_amd64 as a component of Red Hat OpenShift for Windows Containers 10.21; registry.redhat.io/openshift4-wincw/windows-machine-config-rhel9-operator@sha256:3aacd9560f3408becf4b3618590a620d72aff0313a5efb23542552a6fd59500f_amd64 as a component of Red Hat OpenShift for Windows Containers 10.22
    After
    openshift4-wincw/windows-machine-config-rhel8-operator as a component of Red Hat OpenShift Container Platform 4; openshift4-wincw/windows-machine-config-rhel9-operator as a component of Red Hat OpenShift Container Platform 4 · Fixed: registry.redhat.io/openshift4-wincw/windows-machine-config-rhel9-operator@sha256:c5ffbe845d71ab95834ee74201fca1147954d6c3943042720831e06230228d8e_amd64 as a component of OpenShift Windows Machine Config Operator 10.21; registry.redhat.io/openshift4-wincw/windows-machine-config-rhel9-operator@sha256:3aacd9560f3408becf4b3618590a620d72aff0313a5efb23542552a6fd59500f_amd64 as a component of Red Hat OpenShift for Windows Containers 10.22
    Red Hat Product Security ↗
  4. Vendor guidanceAuthoritative vendor guidance changed: removed vendor advisory: access.redhat.com/RHSA-2026:61780.
    Before
    remediation: access.redhat.com/RHSA-2026:47173 · vendor advisory: access.redhat.com/CVE-2026-54100 · vendor advisory: access.redhat.com/RHSA-2026:61780 · 2 more references
    After
    remediation: access.redhat.com/RHSA-2026:47173 · vendor advisory: access.redhat.com/CVE-2026-54100 · vendor advisory: bugzilla.redhat.com/show_bug.cgi?id=2487953 · 1 more references
    access.redhat.com ↗
  5. Vendor guidanceAuthoritative vendor guidance changed: added remediation: access.redhat.com/RHSA-2026:47173; removed remediation: access.redhat.com/RHSA-2026:61780.
    Before
    remediation: access.redhat.com/RHSA-2026:61780 · vendor advisory: access.redhat.com/CVE-2026-54100 · vendor advisory: access.redhat.com/RHSA-2026:61780 · 2 more references
    After
    remediation: access.redhat.com/RHSA-2026:47173 · vendor advisory: access.redhat.com/CVE-2026-54100 · vendor advisory: access.redhat.com/RHSA-2026:61780 · 2 more references
    access.redhat.com ↗
  6. Vendor guidanceAuthoritative vendor guidance changed: added remediation: access.redhat.com/RHSA-2026:61780; added vendor advisory: access.redhat.com/RHSA-2026:61780; removed remediation: access.redhat.com/RHSA-2026:47173.
    Before
    remediation: access.redhat.com/RHSA-2026:47173 · vendor advisory: access.redhat.com/CVE-2026-54100 · vendor advisory: bugzilla.redhat.com/show_bug.cgi?id=2487953 · 1 more references
    After
    remediation: access.redhat.com/RHSA-2026:61780 · vendor advisory: access.redhat.com/CVE-2026-54100 · vendor advisory: access.redhat.com/RHSA-2026:61780 · 2 more references
    access.redhat.com ↗
  7. Affected versionsThe structured affected or fixed version information changed.
    Before
    See the vendor and CVE records for the affected range. · Fixed: 1783692800 < *
    After
    See the vendor and CVE records for the affected range. · Fixed: 1787065708 < *; 1783692800 < *
    CNA ↗
  8. Affected versionsThe structured affected or fixed version information changed.
    Before
    See the vendor and CVE records for the affected range. · Fixed: 1787065708 < *; 1783692800 < *
    After
    See the vendor and CVE records for the affected range. · Fixed: Red Hat OpenShift for Windows Containers 10.22: 1783692800 < *
    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-2026-38234↗Vendor advisory↗Vendor advisory↗Vendor advisory↗CVE authority or vendor reference · Red Hat RHSA-2026:47173↗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-2026-54100 · cve.blacktree.nl