CVE-2026-39961

Aiven Operator has cross-namespace secret exfiltration via ClickhouseUser connInfoSecretSource

MEDIUM
4.9
CVSS Score
Published: April 9, 2026 at 05:14 PM UTC
Updated: October 26, 2026 at 09:10 PM UTC
1 product affected across 1 vendorAiven Operator

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Severity
MEDIUM4.9
Exploit prediction
EPSS 0.4%
SSVC
No known exploit

Description

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.

Affected

Our own answer: ranges merged, affected separated from platform-only, with confidence and review flags.

0.31.0 ≤ v < 0.37.0
Affected range stops below 0.37.0, so it looks safe — our inference, not a vendor statement

Remediation

No guide yet

No remediation guidance has been written for this CVE yet. What the record does show:

References (3)

SSVC — Action Prioritization

SSVCNo known exploitNot automatablePartial impact

SSVC signals action urgency (what to patch first), separate from CVSS which measures severity.

CVSS

Attack Vector
NETWORK
Complexity
LOW
Privileges
HIGH
User Interaction
NONE
Scope
UNCHANGED
Confidentiality
HIGH
Integrity
NONE
Availability
NONE
Vector?

Quick Info

StatusANALYZED
CWE
CWE-269CWE-441

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