CVE-2026-39961: Aiven Operator has cross-namespace secret exfiltration via ClickhouseUser connInfoSecretSource
Impact 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.
Patches
This vulnerability is resolved in version 0.37.0. We recommend all users update as soon as possible.
Credits
Credits to Andrés Cruciani for finding and reporting the bug through our bug bounty program
Other sources
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.
— NVD
Affected Software
Remediation
Event History
Frequently Asked Questions
What is the severity of CVE-2026-39961?
CVE-2026-39961 has been classified with a high severity due to the potential for unauthorized secret exfiltration from multiple namespaces.
How do I fix CVE-2026-39961?
To fix CVE-2026-39961, upgrade the Aiven Operator to version 0.37.0 or later.
Who is affected by CVE-2026-39961?
Developers with create permission on ClickhouseUser CRDs in their namespace are affected by CVE-2026-39961.
What types of sensitive information can be exfiltrated through CVE-2026-39961?
CVE-2026-39961 allows exfiltration of sensitive information such as production database credentials, API keys, and service tokens.
When was CVE-2026-39961 disclosed?
CVE-2026-39961 was disclosed as part of the security advisories related to the Aiven Operator's vulnerabilities.