kuma-dp connects to control plane without verifying TLS certificate when no CA is configured

Overview

When kuma-dp is started against an HTTPS control plane and the operator did not pass a CA certificate, the data plane connects with TLS peer verification disabled. The dataplane authentication token is sent over this unverified connection

Impact

An on-path attacker can intercept the dataplane authentication token and impersonate the control plane to the data plane, allowing them to inject a forged bootstrap configuration and take over the proxy

Affected configurations

• Universal mode kuma-dp started against an HTTPS control plane without --ca-cert-file (or KUMA_CONTROL_PLANE_CA_CERT unset)

Not affected

• Kubernetes installs done through the standard installers (kumactl install control-plane or the official Helm chart). In both cases the control plane's mutating admission webhook injects KUMA_CONTROL_PLANE_CA_CERT into every sidecar at pod admission, so each kuma-dp starts with the CA already configured

Workarounds

Set --ca-cert-file (or KUMA_CONTROL_PLANE_CA_CERT) on every Universal mode data plane and point it at the control plane's serving CA. Alternatively, terminate the control plane behind a publicly trusted certificate; the patched releases will verify successfully against the operating system trust store with no further configuration

Resources

• Fix: https://github.com/kumahq/kuma/pull/16777

Affected packages

• github.com/kumahq/kuma/v2 < 2.7.26
• github.com/kumahq/kuma/v2 >= 2.8.0, < 2.9.16
• github.com/kumahq/kuma/v2 >= 2.10.0, < 2.11.14
• github.com/kumahq/kuma/v2 >= 2.12.0, < 2.12.11
• github.com/kumahq/kuma/v2 >= 2.13.0, < 2.13.7
• github.com/kumahq/kuma <= 1.8.1

Remediation

Upgrade to a patched release:

• github.com/kumahq/kuma/v2 2.7.26
• github.com/kumahq/kuma/v2 2.9.16
• github.com/kumahq/kuma/v2 2.11.14
• github.com/kumahq/kuma/v2 2.12.11
• github.com/kumahq/kuma/v2 2.13.7