CVE-2026-18679

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, and the dataplane authentication token is sent over that unverified connection.

An on-path actor can intercept the dataplane authentication token and impersonate the control plane to the data plane, injecting a forged bootstrap configuration and taking over the proxy.

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, and the dataplane authentication token is sent over that unverified connection.

An on-path actor can intercept the dataplane authentication token and impersonate the control plane to the data plane, injecting a forged bootstrap configuration and taking over the proxy.

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, and the dataplane authentication token is sent over that unverified connection.

An on-path actor can intercept the dataplane authentication token and impersonate the control plane to the data plane, injecting a forged bootstrap configuration and taking over the proxy.

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, and the dataplane authentication token is sent over that unverified connection.

An on-path actor can intercept the dataplane authentication token and impersonate the control plane to the data plane, injecting a forged bootstrap configuration and taking over the proxy.

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, and the dataplane authentication token is sent over that unverified connection.

An on-path actor can intercept the dataplane authentication token and impersonate the control plane to the data plane, injecting a forged bootstrap configuration and taking over the proxy.

Kuma is a modern Envoy-based service mesh that can run on every cloud across both Kubernetes and VMs. Prior to 2.7.26, 2.9.16, 2.11.14, 2.12.11, and 2.13.7, Universal mode kuma-dp connections to an HTTPS control plane disable TLS peer verification when --ca-cert-file is not supplied and KUMA_CONTROL_PLANE_CA_CERT is unset. The dataplane authentication token is sent over the unverified connection, allowing an on-path attacker to intercept the token, impersonate the control plane, inject a forged bootstrap configuration, and take over the proxy. Standard Kubernetes installations created by kumactl install control-plane or the official Helm chart are unaffected because the mutating admission webhook injects KUMA_CONTROL_PLANE_CA_CERT into each sidecar. This issue is fixed in versions 2.7.26, 2.9.16, 2.11.14, 2.12.11, and 2.13.7.

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

kuma-dp connects to control plane without verifying TLS certificate when no CA is configured in github.com/kumahq/kuma.

NOTE: The source advisory for this report contains additional versions that could not be automatically mapped to standard Go module versions.

(If this is causing false-positive reports from vulnerability scanners, please suggest an edit to the report.)

The additional affected modules and versions are: github.com/kumahq/kuma/v2 from v2.8.0 before v2.9.16.