[IMPORTANT] [SECURITY] CVE-2025-66623: Unrestricted access to all Secrets in the same Kubernetes namespace from Kafka Connect and MirrorMaker 2 operands

[scholzj]

In some situations, Strimzi creates an incorrect Kubernetes Role which grants the Apache Kafka Connect and Apache Kafka MirrorMaker 2 operands the GET access to all Kubernetes Secrets that exist in the given Kubernetes namespace. The exact scenario when this happens is when:

• Apache Kafka Connect is deployed without at least one of the following options configured:
  • TLS encryption with configured trusted certificates (no .spec.tls.trustedCertificates section in the KafkaConnect CR)
  • mTLS authentication (no type: tls in .spec.authentication section of the KafkaConnect CR)
  • TLS encryption with configured trusted certificates for type: oauth authentication (no .spec.authentication.tlsTrustedCertificates section in the KafkaConnect CR)
• Apache Kafka MirrorMaker2 is deployed without at least one of the following options configured for the target cluster:
  • TLS encryption with configured trusted certificates (no .spec.target.tls.trustedCertificates section in the KafkaConnect CR)
  • mTLS authentication (no type: tls in .spec.target.authentication section of the KafkaConnect CR)
  • TLS encryption with configured trusted certificates for type: oauth authentication (no .spec.target.authentication.tlsTrustedCertificates section in the KafkaConnect CR)
  • TLS encryption with configured trusted certificates (no .spec.clusters[].tls.trustedCertificates section in the KafkaConnect CR for the target cluster)
  • mTLS authentication (no type: tls in .spec.clusters[].authentication section of the KafkaConnect CR for the target cluster)
  • TLS encryption with configured trusted certificates for type: oauth authentication (no .spec.clusters[].authentication.tlsTrustedCertificates section in the KafkaConnect CR for the target cluster)

When the operands configured as described above are deployed with Strimzi >= 0.47.0 and <= 0.49.0, any code running within their Pods and using their Service Account for authentication will be able to GET any Kubernetes Secret from the same namespace. This can be done by executing 3rd party tools from the Pods. Or directly from the Kafka Connect code, for example, using configuration providers or HTTP connectors. The Pods are allowed to only GET the Secrets. They are not allowed to list, watch, modify, or delete the Secrets.

This CVE is fixed in the recent Strimzi 0.49.1 release. We recommend upgrading to it.

For more information, see GHSA-xrhh-hx36-485q

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Examples of affected custom resource configurations:

• Kafka Connect

  apiVersion: kafka.strimzi.io/v1
  kind: KafkaConnect
  metadata:
    name: my-connect-cluster
  spec:
    version: 4.1.1
    replicas: 1
    bootstrapServers: my-cluster-kafka-bootstrap:9092
    groupId: my-connect-group
    configStorageTopic: my-connect-configs
    statusStorageTopic: my-connect-status
    offsetStorageTopic: my-connect-offsets
    config:
      config.storage.replication.factor: -1
      offset.storage.replication.factor: -1
      status.storage.replication.factor: -1

• Kafka MirrorMaker 2

  apiVersion: kafka.strimzi.io/v1
  kind: KafkaMirrorMaker2
  metadata:
    name: my-mirror-maker-2
  spec:
    version: 4.1.1
    replicas: 1
    target:
      alias: cluster-b
      bootstrapServers: cluster-b-kafka-bootstrap:9092
      groupId: my-mirror-maker-2-group
      configStorageTopic: my-mirror-maker-2-config
      offsetStorageTopic: my-mirror-maker-2-offset
      statusStorageTopic: my-mirror-maker-2-status
      config:
        # -1 means it will use the default replication factor configured in the broker
        config.storage.replication.factor: -1
        offset.storage.replication.factor: -1
        status.storage.replication.factor: -1
    mirrors:
    - source:
        bootstrapServers: cluster-a-kafka-bootstrap:9092
        alias: cluster-a
      sourceConnector:
        tasksMax: 1
        config:
          # -1 means it will use the default replication factor configured in the broker
          replication.factor: -1
          offset-syncs.topic.replication.factor: -1
          sync.topic.acls.enabled: "false"
          refresh.topics.interval.seconds: 600
      checkpointConnector:
        tasksMax: 1
        config:
          # -1 means it will use the default replication factor configured in the broker
          checkpoints.topic.replication.factor: -1
          sync.group.offsets.enabled: "false"
          refresh.groups.interval.seconds: 600
      topicsPattern: ".*"
      groupsPattern: ".*"