Aiven Operator has cross-namespace secret exfiltration via ClickhouseUser connInfoSecretSource

CVE-2026-39961 → View on GitHub ↗ View on CVE.org ↗ View on NVD ↗

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

Basic information

Type
reviewed
Severity
medium
Advisory on GitHub
Open advisory ↗
Repository advisory
Open repository advisory ↗
Source code
Browse source ↗
Published (advisory)
2026-04-10 17:22:00 UTC
Updated
2026-04-10 17:22:00 UTC
GitHub reviewed
2026-04-10 17:22:00 UTC
NVD published
2026-04-09

EPSS Score

Score Percentile
0.03% 9.23%

CVSS Scores

Base score Version Severity Vector
6.8 3.1 —
CVSS:3.1/AV:N/AC:L/PR:H/UI:N/S:C/C:H/I:N/A:N Click to expand
Attack vector (AV:N)
Could be attacked over the internet or any normal routed network—not just someone sitting at the machine.
Attack complexity (AC:L)
Once they can reach the bug, pulling it off is straightforward—no weird race conditions or rare setup.
Privileges required (PR:H)
They need powerful rights—admin, root, or similar—before this pays off.
User interaction (UI:N)
Nobody has to click “OK” or open a trap file; it can work without a victim helping.
Scope (S:C)
Breaking this can reach past the original component and bite other resources—bigger blast radius.
Confidentiality (C:H)
Serious risk that confidential data gets exposed in a big way.
Integrity (I:N)
Data isn’t meaningfully altered or forged.
Availability (A:N)
Service keeps running; no real outage angle.

Identifiers

Type Value
GHSA GHSA-99j8-wv67-4c72 ↗
CVE CVE-2026-39961 ↗

CWEs

CWE id Name
CWE-269 Improper Privilege Management
CWE-441 Unintended Proxy or Intermediary ('Confused Deputy')

Credits

  • AndresAIFR (finder)

Affected packages (1)

Vulnerable version ranges and first patched releases as published by GitHub.

Ecosystem Package Vulnerable range First patched Vulnerable functions
go github.com/aiven/aiven-operator >= 0.31.0, < 0.37.0 0.37.0 —

References

cvelogic Threat Intelligence