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KubernetesApplication

CVE-2023-2727

MEDIUM · 6.5 CVSS v3.1 Published 2023-07-03
Fix available
A fix is available. Upgrade to after 1.27.2 or later.
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
Users may be able to launch containers using images that are restricted by ImagePolicyWebhook when using ephemeral containers. Kubernetes clusters are only affected if the ImagePolicyWebhook admission plugin is used together with ephemeral containers.

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 · high confidence

In Kubernetes, the ImagePolicyWebhook admission plugin is meant to enforce policies restricting which container images can be deployed. However, when ephemeral containers (a feature for debugging running pods) are used, the ImagePolicyWebhook enforcement is bypassed, allowing users to launch containers with images that should be blocked by policy.

MitigationDisable ephemeral containers if not needed, or update Kubernetes to a version where the ImagePolicyWebhook properly validates ephemeral container images. Consider using a different admission controller (like OPA/Gatekeeper) that properly handles ephemeral containers as a longer-term solution.

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
KubernetesApplication
Affected:<= 1.24.14>= 1.25.0, <= 1.25.10>= 1.26.0, <= 1.26.5>= 1.27.0, <= 1.27.2

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
High
User interaction
None
Scope
Unchanged
Confidentiality
High
Integrity
High
Availability
None

CVSS:3.1/AV:N/AC:L/PR:H/UI:N/S:U/C:H/I:H/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 Kubernetes API server version
    Run `kubectl get nodes` to see kubelet versions, or check the kube-apiserver pod/container version in the control plane. Compare against affected ranges: <= 1.24.14, 1.25.0-1.25.10, 1.26.0-1.26.5, or 1.27.0-1.27.2
    Affected if The Kubernetes version falls within any of the affected version ranges listed in the CVE
  2. Verify ImagePolicyWebhook admission plugin is enabled
    Check the kube-apiserver configuration for the `--enable-admission-plugins` or `--admission-control-config-file` flags. Look for ImagePolicyWebhook in the enabled plugins list
    Affected if ImagePolicyWebhook is listed in the enabled admission plugins
  3. Confirm ephemeral containers feature can be used
    Verify the EphemeralContainers feature gate is enabled on the API server (typically in the kube-apiserver manifest). Also verify RBAC permissions allow creating ephemeral containers via `kubectl auth can-i create ephemeralcontainers`
    Affected if The EphemeralContainers feature gate is enabled and users have permission to create ephemeral containers

If your Kubernetes version is in the affected range AND ImagePolicyWebhook is enabled AND ephemeral containers feature is active, then your environment is vulnerable to bypassed image policy enforcement.

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.

dbcve · scoped
Upgrade available Upgrade to a release after 1.27.2
Interim mitigation

Disable ephemeral containers if not needed, or update Kubernetes to a version where the ImagePolicyWebhook properly validates ephemeral container images. Consider using a different admission controller (like OPA/Gatekeeper) that properly handles ephemeral containers as a longer-term solution.

Recommended fix High confidence

Kubernetes 1.24.15, 1.25.11, 1.26.6, or 1.27.3 (depending on your current minor version)

  1. 1. Identify the current Kubernetes version by running: kubectl get nodes -o wide or checking the kubelet version on nodes
  2. 2. Determine which Kubernetes release line you're running (1.24.x, 1.25.x, 1.26.x, or 1.27.x)
  3. 3. Plan the upgrade to the fixed version corresponding to your release line: 1.24.15 for 1.24.x, 1.25.11 for 1.25.x, 1.26.6 for 1.26.x, or 1.27.3 for 1.27.x
  4. 4. Review the Kubernetes upgrade documentation at https://kubernetes.io/docs/tasks/administer-cluster/upgrade/
  5. 5. Before upgrading, backup etcd data and verify cluster state: kubectl get all --all-namespaces -o yaml > cluster-backup.yaml
  6. 6. Upgrade the control plane first following your infrastructure provider's procedures (kubeadm, managed Kubernetes, or manual)
  7. 7. Upgrade kubelet on all nodes after the control plane is stable
  8. 8. Verify the upgrade by checking: kubectl version --short, kubectl get nodes, and confirm all pods are Running
Caveat Minor version upgrades within the same major version typically have minimal breaking changes, but review the CHANGELOG for your target version for any known issues, and test in a staging environment first

Generated from the published advisory — verify against the referenced sources before acting.

Fix this in Kubernetes Scoped from the published advisory
  • Consultation3.0 h
  • Implementation4.0 h
  • Testing3.0 h
  • Review / QA2.0 h
12.0 hours of engineering $2,130
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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-2023-2727 in production — separate from our analysis above.

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What this is

A place for practitioners to share what actually worked: a mitigation you’ve tested, a configuration change, a version- or environment-specific caveat, or a link to a verified patch. The most useful notes rise to the top as peers upvote them, so the signal stays high.

What belongs here
  • Verified mitigations, workarounds, and config changes
  • Version or environment caveats, and links to real fixes
  • No weaponised exploit code, or anything meant to cause harm
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