Vulnerabilities

Calico's Application Layer Policy (disabled by default), which enforces HTTP rules through Dikastes, fails to perform URL path normalization. As a result, HTTP requests using path-traversal segments, encoded slashes, or repeated slashes are not correctly evaluated by Prefix path rules. Dikastes authorizes the request under the permitted prefix while the downstream workload or a fronting proxy normalizes the path and serves the restricted endpoint. An attacker with network access and no special RBAC can potentially reach HTTP endpoints the policy was intended to restrict.

In Calico, the install-cni init container logs the rendered CNI configuration to standard output. When the configuration template uses the __SERVICEACCOUNT_TOKEN__ placeholder (Canal/Flannel-Calico deployments), the installer substitutes the live Kubernetes ServiceAccount bearer token before logging, exposing the token to any authenticated user with pods/log permission in the namespace with calico-node. The token holds patch privileges on pods/status, enabling annotation-based attacks against cluster workloads. The default kubeconfig-based authentication path is not affected. This is a direct regression of TTA-2018-001.

In certain conditions for Calico Typha (v3.26.2, v3.25.1 and below), and Calico Enterprise Typha (v3.17.1, v3.16.3, v3.15.3 and below), a client TLS handshake can block the Calico Typha server indefinitely, resulting in denial of service. The TLS Handshake() call is performed inside the main server handle for loop without any timeout allowing an unclean TLS handshake to block the main loop indefinitely while other connections will be idle waiting for that handshake to finish.

Clusters using Calico (version 3.22.1 and below), Calico Enterprise (version 3.12.0 and below), may be vulnerable to route hijacking with the floating IP feature. Due to insufficient validation, a privileged attacker may be able to set a floating IP annotation to a pod even if the feature is not enabled. This may allow the attacker to intercept and reroute traffic to their compromised pod.