When Calico is configured with the Azure IPAM plugin, the Calico CNI binary mutates the incoming CNI configuration to attach subnet information before delegating to the IPAM plugin. After mutating, the Azure IPAM helper logs the entire unmarshaled configuration map (stdinData) at INFO level to /var/log/calico/cni/cni.log on every CNI ADD and DEL invocation — once per pod scheduled or terminated on the node. When the cluster is deployed using token-based Kubernetes authentication, this log entry contains the ServiceAccount token, client key, and certificate authority in plaintext. Any principal with read access to /var/log/calico/cni/cni.log on a node  can read these logs and extract the credentials, which grant cluster-wide Calico networking admin privileges.

When calicoctl is invoked with --log-level=info or --log-level=debug, the client prints the full contents of its loaded connection-configuration struct to stderr in a single log line. The struct embeds every credential calicoctl uses to talk to the cluster — inline kubeconfig (with bearer token), Kubernetes API bearer token, etcd password, and inline PEM-encoded etcd client certificate and key. Any reader of that stderr stream — CI job logs, session-recording archives, shared support-ticket transcripts, or local filesystem viewers on the host that ran calicoctl — can extract these credentials with zero Kubernetes privilege. calicoctl's default log level is panic, so this issue only triggers when verbose logging is explicitly enabled.

In vulnerable versions of Calico (v3.27.2 and below), Calico Enterprise (v3.19.0-1, v3.18.1, v3.17.3 and below), and Calico Cloud (v19.2.0 and below), an attacker who has local access to the Kubernetes node, can escalate their privileges by exploiting a vulnerability in the Calico CNI install binary. The issue arises from an incorrect SUID (Set User ID) bit configuration in the binary, combined with the ability to control the input binary, allowing an attacker to execute an arbitrary binary with elevated privileges.