CVE-2025-64432: KubeVirt Affected by an Authentication Bypass in Kubernetes Aggregation Layer

Severity: medium (CVSS 4.7 v3.1)
Exploited in the wild: not listed in CISA KEV
EPSS: 0.1% probability of exploitation in the next 30 days
Public exploit or detection template: yes
Published: 2025-11-07 · updated 2026-06-17
Weakness: CWE-287

Description

KubeVirt is a virtual machine management add-on for Kubernetes. Versions 1.5.3 and below, and 1.6.0 contained a flawed implementation of the Kubernetes aggregation layer's authentication flow which could enable bypass of RBAC controls. It was discovered that the virt-api component fails to correctly authenticate the client when receiving API requests over mTLS. In particular, it fails to validate the CN (Common Name) field in the received client TLS certificates against the set of allowed values defined in the extension-apiserver-authentication configmap. Failre to validate certain fields in the client TLS certificate may allow an attacker to bypass existing RBAC controls by directly communicating with the aggregated API server, impersonating the Kubernetes API server and its aggregator component. This issue is fixed in versions 1.5.3 and 1.6.1.

Affected products

kubevirt: before 1.5.3; 1.6.0, 1.6.0-rc0, 1.6.0-rc1 — fixed in 1.5.3

How to fix

Upgrade to a fixed version: kubevirt 1.5.3. Check the vendor advisory for mitigations.

References

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