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Openshift Container PlatformApplication · Redhat

CVE-2026-42965

MEDIUM · 6.5 CVSS v3.1 Published 2026-05-29
Mitigation only
No fix yet — a mitigation exists. There is no fixed release. A documented workaround reduces exposure in the meantime.
See remediation →
71/100
Remediation priority · Elevated
Remotely reachable Zero-click

Official description Straight from the sourceThe vendor's or NVD's own wording, published unedited. Authoritative, but often terse — it says what broke, rarely what to do.

NVD · unedited
A flaw was found in the OpenShift Router. A user with EndpointSlice write access can exploit this vulnerability by creating a Service backed by an FQDN (Fully Qualified Domain Name) EndpointSlice that resolves to a cloud metadata endpoint. This allows the router to proxy requests to the cloud metadata endpoint, leading to the disclosure of instance credentials and other sensitive metadata. This bypasses previous security measures for validating IP addresses.

Technical summary Written by usOur analysis, written from the advisory, the CVSS vector and the affected-version data. It adds context the advisory leaves out, and never invents facts that are not in the source.

dbcve analysis · moderate confidence

The OpenShift Router does not properly validate FQDN-based EndpointSlices before proxying requests. An attacker with EndpointSlice write access can create a Service using an FQDN that resolves to a cloud metadata endpoint (e.g., 169.254.169.254), causing the router to proxy requests and leak instance credentials. This bypasses previous IP-based validation measures.

MitigationImplement DNS resolution validation for EndpointSlices before routing, and explicitly deny/proxy to known cloud metadata IP ranges (e.g., 169.254.169.254). Consider restricting EndpointSlice write permissions to prevent exploitation.

Verify against the referenced sources before acting — the references below are authoritative for this CVE, this summary is not.

Affected products & versions What the vendor confirmedThe version ranges the vendor confirmed as vulnerable. If your version sits inside a range here, treat yourself as exposed until you have upgraded.

NVD · CPE data
Openshift Container PlatformApplication
Affected:= 4.0
Openshift RouterApplication
Affected:all versions

CVSS breakdown How the score is builtThe industry scoring standard. It rates how the flaw is reached, what it takes to exploit, and what an attacker gains — the score is derived from those, not the other way round.

From the vector
Attack vector
Network
Complexity
Low
Privileges
Low
User interaction
None
Scope
Unchanged
Confidentiality
High
Integrity
None
Availability
None

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

Am I affected? How to checkSteps we derive from the advisory and the affected-version data, so you can decide whether this CVE reaches your setup. They are a guide, not a scan — your own configuration is the authority.

dbcve checks

Work through these to decide whether this CVE applies to you.

  1. Check OpenShift platform version
    Run 'oc get clusterversion version' to retrieve the installed OpenShift Container Platform version
    Affected if The installed version is 4.0 or any version where the router handles EndpointSlices with FQDN-based endpoints
  2. Identify EndpointSlices with cloud metadata IP destinations
    Use 'oc get endpointslices --all-namespaces -o json' and inspect the 'addresses' field for IP ranges 169.254.0.0/16 (AWS), 169.254.169.254 (Azure/GCP metadata), or other known cloud metadata IPs
    Affected if Any EndpointSlice exists with addresses in cloud metadata IP ranges that a Service references
  3. Check Services referencing potentially malicious EndpointSlices
    Run 'oc get services --all-namespaces -o json' and cross-reference with EndpointSlice addresses to identify Services routing to cloud metadata IPs
    Affected if A Service exists that selects EndpointSlices containing cloud metadata IP addresses
  4. Review router configuration for FQDN-based endpoint handling
    Inspect the OpenShift Router deployment configuration (typically in openshift-ingress namespace) for any settings related to endpoint validation or FQDN resolution behavior
    Affected if Router configuration lacks explicit blocking of cloud metadata IP ranges or does not validate FQDN-resolved addresses in EndpointSlices
  5. Audit RBAC for EndpointSlice write permissions
    Run 'oc auth can-i create endpointslices --as=<user>' for various service accounts and users, or inspect ClusterRoleBindings for permissions to create or modify EndpointSlices in target namespaces
    Affected if Users or service accounts have broad permissions to create or modify EndpointSlices without restrictions

You are affected if your OpenShift Router processes EndpointSlices that resolve to cloud metadata IP addresses (particularly 169.254.0.0/16 range) due to missing FQDN-based endpoint validation, regardless of OpenShift version.

Generated from the published advisory. Verify against your own configuration.

Check your environment

Paste your version and any relevant configuration and it will be compared against the affected criteria above. Do not include secrets or credentials.

AI-assisted, checked against the advisory. Informational, not a guarantee.

Remediation Closing itWhat it takes to close this. Where a vendor fix exists we point at it; where none exists we say so plainly, and can build one. Effort estimates are scoped from the advisory, not from your codebase.

From vendor data
Mitigation available No clean upgrade yet — mitigate in the meantime
Mitigation

Implement DNS resolution validation for EndpointSlices before routing, and explicitly deny/proxy to known cloud metadata IP ranges (e.g., 169.254.169.254). Consider restricting EndpointSlice write permissions to prevent exploitation.

Fix this in Openshift Container Platform Scoped from the published advisory
  • Consultation6.0 h
  • Implementation12.0 h
  • Testing8.0 h
  • Review / QA4.0 h
30.0 hours of engineering $5,280
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References Go to the primary sourcePrimary sources — vendor advisories, patches and trackers. Where our summary and a reference disagree, the reference wins.

Primary sources

Practitioner notes

Contributed

Peer-ranked notes from engineers who’ve handled CVE-2026-42965 in production — separate from our analysis above.

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