CVE-2022-23635: Unauthenticated control plane denial of service attack in Istio

Severity: high (CVSS 7.5 v3.1)
Exploited in the wild: not listed in CISA KEV
EPSS: 1.7% probability of exploitation in the next 30 days
Public exploit or detection template: none known
Published: 2022-02-22 · updated 2026-06-17
Weakness: CWE-287

Description

Istio is an open platform to connect, manage, and secure microservices. In affected versions the Istio control plane, `istiod`, is vulnerable to a request processing error, allowing a malicious attacker that sends a specially crafted message which results in the control plane crashing. This endpoint is served over TLS port 15012, but does not require any authentication from the attacker. For simple installations, Istiod is typically only reachable from within the cluster, limiting the blast radius. However, for some deployments, especially [multicluster](https://istio.io/latest/docs/setup/install/multicluster/primary-remote/) topologies, this port is exposed over the public internet. There are no effective workarounds, beyond upgrading. Limiting network access to Istiod to the minimal set of clients can help lessen the scope of the vulnerability to some extent.

Affected products

istio: before 1.11.7; from 1.12.0 before 1.12.4; from 1.13.0 before 1.13.1 — fixed in 1.11.7, 1.12.4, 1.13.1

How to fix

Upgrade to a fixed version: istio 1.11.7, 1.12.4, 1.13.1. Check the vendor advisory for mitigations.

References

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