CVE-2026-39961
Aiven Operator has cross-namespace secret exfiltration via ClickhouseUser connInfoSecretSource
Description
### 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](https://bugcrowd.com/aiven-mbb-og)
How to fix CVE-2026-39961
To remediate CVE-2026-39961, upgrade the affected package to a fixed version below.
- —upgrade to 0.37.0 or later
Is CVE-2026-39961 being exploited?
Low — EPSS is 0.0%, meaning exploitation activity has not been observed at scale.
Affected packages (1)
- >= 0.31.0, < 0.37.0
CVSS scores
| Source | Version | Severity | Vector |
|---|---|---|---|
| osv | CVSS 3.1 | MEDIUM6.8 | CVSS:3.1/AV:N/AC:L/PR:H/UI:N/S:C/C:H/I:N/A:N |