CVE-2026-39961 MEDIUM

CVE-2026-39961: Aiven Operator has cross-namespace secret exfiltration via ClickhouseUser connInfoSecretSource

Vendor Aiven
Product aiven-operator
Weakness CWE-269
Published April 9, 2026
Last update April 10, 2026

CVSS base score

6.8/10
Attack vector Network
Attack complexity Low
Privileges required High
User interaction None
Confidentiality High
Integrity None

CVSS vector

CVSS:3.1/AV:N/AC:L/PR:H/UI:N/S:C/C:H/I:N/A:N

What the vulnerability does

01Description

Aiven Operator allows you to provision and manage Aiven Services from your Kubernetes cluster. From 0.31.0 to before 0.37.0, a developer with create permission on ClickhouseUser CRDs in their own namespace can exfiltrate secrets from any other namespace — production database credentials, API keys, service tokens — with a single kubectl apply. The operator reads the victim's secret using its ClusterRole and writes the password into a new secret in the attacker's namespace. The operator acts as a confused deputy: its ServiceAccount has cluster-wide secret read/write (aiven-operator-role ClusterRole), and it trusts user-supplied namespace values in spec.connInfoSecretSource.namespace without validation. No admission webhook enforces this boundary — the ServiceUser webhook returns nil, and no ClickhouseUser webhook exists. This vulnerability is fixed in 0.37.0.

Key dates

02Disclosure timeline

April 9, 2026 CVE published
April 10, 2026 Record updated