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Aiven Operator has cross-namespace secret exfiltration via ClickhouseUser connInfoSecretSource

Moderate severity GitHub Reviewed Published Apr 9, 2026 in aiven/aiven-operator

Package

gomod github.com/aiven/aiven-operator (Go)

Affected versions

>= 0.31.0, < 0.37.0

Patched versions

0.37.0

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

References

@DocEmmetBrown DocEmmetBrown published to aiven/aiven-operator Apr 9, 2026
Published by the National Vulnerability Database Apr 9, 2026
Published to the GitHub Advisory Database Apr 10, 2026
Reviewed Apr 10, 2026

Severity

Moderate

CVSS overall score

This score calculates overall vulnerability severity from 0 to 10 and is based on the Common Vulnerability Scoring System (CVSS).
/ 10

CVSS v3 base metrics

Attack vector
Network
Attack complexity
Low
Privileges required
High
User interaction
None
Scope
Changed
Confidentiality
High
Integrity
None
Availability
None

CVSS v3 base metrics

Attack vector: More severe the more the remote (logically and physically) an attacker can be in order to exploit the vulnerability.
Attack complexity: More severe for the least complex attacks.
Privileges required: More severe if no privileges are required.
User interaction: More severe when no user interaction is required.
Scope: More severe when a scope change occurs, e.g. one vulnerable component impacts resources in components beyond its security scope.
Confidentiality: More severe when loss of data confidentiality is highest, measuring the level of data access available to an unauthorized user.
Integrity: More severe when loss of data integrity is the highest, measuring the consequence of data modification possible by an unauthorized user.
Availability: More severe when the loss of impacted component availability is highest.
CVSS:3.1/AV:N/AC:L/PR:H/UI:N/S:C/C:H/I:N/A:N

EPSS score

Exploit Prediction Scoring System (EPSS)

This score estimates the probability of this vulnerability being exploited within the next 30 days. Data provided by FIRST.
(9th percentile)

Weaknesses

Improper Privilege Management

The product does not properly assign, modify, track, or check privileges for an actor, creating an unintended sphere of control for that actor. Learn more on MITRE.

Unintended Proxy or Intermediary ('Confused Deputy')

The product receives a request, message, or directive from an upstream component, but the product does not sufficiently preserve the original source of the request before forwarding the request to an external actor that is outside of the product's control sphere. This causes the product to appear to be the source of the request, leading it to act as a proxy or other intermediary between the upstream component and the external actor. Learn more on MITRE.

CVE ID

CVE-2026-39961

GHSA ID

GHSA-99j8-wv67-4c72

Source code

Credits

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