Skip to main content

2 posts tagged with "cve"

View All Tags

· 2 min read
Ivan Sim

This article provides information and mitigation steps for the following vulnerabilities in Harvester:

important

These vulnerabilities affect specific versions of the RKE2 ingress-nginx controller (v1.13.7 and earlier, v1.14.3 and earlier). All Harvester versions that use this controller (including 1.5.2 and earlier, 1.6.1 and earlier, and 1.7.0) are therefore affected.

These CVEs are fixed in Harvester 1.7.1 and newer.

important

Harvester does not utilize the ingress-nginx controller custom error backend. Therefore, it is not affected by CVE-2026-24513.

important

Currently, no mitigation is available for CVE-2026-24514. An upgrade to Harvester 1.7.1 is required.

For more information on its CVSS score, see https://www.first.org/cvss/calculator/3.1#CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H

You can confirm the version of the RKE2 ingress-nginx pods by running this command on your Harvester cluster:

kubectl -n kube-system get po -l"app.kubernetes.io/name=rke2-ingress-nginx" -ojsonpath='{.items[].spec.containers[].image}'

If the command returns one of the affected versions, perform one of the following mitigation steps.

The primary resolution is to upgrade to Harvester 1.7.1 or newer, which includes the fixed RKE2 ingress-nginx controller.

If upgrade is not possible, deploy the following validating admission policy to your cluster to reject ingress resources with the vulnerable configuration:

cat<<EOF | kubectl apply -f -
apiVersion: admissionregistration.k8s.io/v1
kind: ValidatingAdmissionPolicy
metadata:
  name: ingress-nginx-annotation-validation
spec:
  failurePolicy: Fail
  matchConstraints:
    resourceRules:
    - apiGroups:   ["networking.k8s.io"]
      apiVersions: ["v1"]
      operations:  ["CREATE", "UPDATE"]
      resources:   ["ingresses"]
  validations:
    - expression: |
        !('nginx.ingress.kubernetes.io/auth-proxy-set-headers' in object.metadata.annotations) &&
        !('nginx.ingress.kubernetes.io/auth-method' in object.metadata.annotations) &&
        (object.spec.rules.all(rule, rule.http.paths.all(path, path.pathType != 'ImplementationSpecific')))
      message: "Ingress resources with the vulnerable annotations are not allowed. Please remove the 'nginx.ingress.kubernetes.io/auth-proxy-set-headers' and 'nginx.ingress.kubernetes.io/auth-method' annotations, and avoid using the 'ImplementationSpecific' path type."
---
apiVersion: admissionregistration.k8s.io/v1
kind: ValidatingAdmissionPolicyBinding
metadata:
  name: ingress-nginx-annotation-validation
spec:
  policyName: ingress-nginx-annotation-validation
  validationActions: [Deny]
EOF
info

This policy is a cluster-scoped resource that requires the proper administrator RBAC permissions to create.

This validating policy rejects any ingress resources that contain the:

  • nginx.ingress.kubernetes.io/auth-proxy-set-headers annotation
  • nginx.ingress.kubernetes.io/auth-method annotation
  • ImplementationSpecific path type

The policy can be removed once you upgrade to Harvester 1.7.1 or newer:

kubectl delete validatingadmissionpolicy ingress-nginx-annotation-validation

kubectl delete validatingadmissionpolicybinding ingress-nginx-annotation-validation

References​

· 3 min read
Ivan Sim
important

CVE-2025-1974 (vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H) has a score of 9.8 (Critical).

The vulnerability affects specific versions of the RKE2 ingress-nginx controller (v.1.11.4 and earlier, and v1.12.0). All Harvester versions that use this controller (including v1.4.2 and earlier) are therefore affected.

This CVE is fixed in Harvester 1.5.0, 1.4.3 and newer.

A security issue was discovered in Kubernetes where under certain conditions, an unauthenticated attacker with access to the pod network can achieve arbitrary code execution in the context of the ingress-nginx controller. This can lead to disclosure of secrets accessible to the controller. (Note that in the default installation, the controller can access all secrets cluster-wide.)

You can confirm the version of the RKE2 ingress-nginx pods by running this command on your Harvester cluster:

kubectl -n kube-system get po -l"app.kubernetes.io/name=rke2-ingress-nginx" -ojsonpath='{.items[].spec.containers[].image}'

If the command returns one of the affected versions, disable the rke2-ingress-nginx-admission validating webhook configuration by performing the following steps:

  1. On one of your control plane nodes, use kubectl to confirm the existence of the HelmChartConfig resource named rke2-ingress-nginx:

    $ kubectl -n kube-system get helmchartconfig rke2-ingress-nginx
    NAME                 AGE
    rke2-ingress-nginx   14d1h

  2. Use kubectl -n kube-system edit helmchartconfig rke2-ingress-nginx to add the following configurations to the resource:

    • .spec.valuesContent.controller.admissionWebhooks.enabled: false
    • .spec.valuesContent.controller.extraArgs.enable-annotation-validation: true

  3. The following is an example of what the updated .spec.valuesContent configuration along with the default Harvester ingress-nginx configuration should look like:

    apiVersion: helm.cattle.io/v1
    kind: HelmChartConfig
    metadata:
      name: rke2-ingress-nginx
      namespace: kube-system
    spec:
      valuesContent: |-
        controller:
          admissionWebhooks:
            port: 8444
            enabled: false
          extraArgs:
            enable-annotation-validation: true
            default-ssl-certificate: cattle-system/tls-rancher-internal
          config:
            proxy-body-size: "0"
            proxy-request-buffering: "off"
          publishService:
            pathOverride: kube-system/ingress-expose

    Exit the kubectl edit command execution to save the configuration.

    Harvester automatically applies the change once the content is saved.

    important

    The configuration disables the RKE2 ingress-nginx admission webhooks while preserving Harvester's default ingress-nginx configuration.

    If the HelmChartConfig resource contains other custom ingress-nginx configuration, you must retain them when editing the resource.

  4. Verify that RKE2 deleted the rke2-ingress-nginx-admission validating webhook configuration.

    $ kubectl get validatingwebhookconfiguration rke2-ingress-nginx-admission
    Error from server (NotFound): validatingwebhookconfigurations.admissionregistration.k8s.io "rke2-ingress-nginx-admission" not found

  5. Verify that the ingress-nginx pods are restarted successfully.

    $ kubectl -n kube-system get po -lapp.kubernetes.io/instance=rke2-ingress-nginx
    NAME                                  READY   STATUS    RESTARTS   AGE
    rke2-ingress-nginx-controller-g8l49   1/1     Running   0          5s

Once your Harvester cluster receives the RKE2 ingress-nginx patch, you can re-install the rke2-ingress-nginx-admission validating webhook configuration by removing the HelmChartConfig patch.

important

These steps only cover the RKE2 ingress-nginx controller that is managed by Harvester. You must also update other running ingress-nginx controllers. See the References section for more information.

References​