CVE-2026-23990Network attack vector

Authenticated data exposure via empty impersonation identity

Published Jan 21, 2026 · Updated Jan 21, 2026

Authorization bypass in ControlPlane Flux Operator 0.36.0 through 0.39.0 allows remote authenticated users to read cluster-wide Flux data. The Web UI claims processor accepts empty username and groups values after CEL evaluation, so client-go omits Kubernetes impersonation headers. Exposure requires an OIDC provider or custom expressions that produce both empty values; resulting requests use the operator service account.

CVSS severity5.3
Medium
EPSS probability0.32%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Authorization bypass in ControlPlane Flux Operator 0.36.0 through 0.39.0 allows remote authenticated users to read cluster-wide Flux data. The Web UI claims processor accepts empty username and groups values after CEL evaluation, so client-go omits Kubernetes impersonation headers. Exposure requires an OIDC provider or custom expressions that produce both empty values; resulting requests use the operator service account.

The record

CVE
CVE-2026-23990
Published
Jan 21, 2026
Updated
Jan 21, 2026
Vendor
ControlPlane
Product
Flux Operator
Classifications
CWE-862, CWE-269, T1190
Attack vector
network
Privileges
authenticated

Timeline

How it unfolded

  1. Jan 21, 2026CVE publishedPublication date reported by the CVE source.
  2. Jan 21, 2026Record updatedLatest update available in the CVE record.

Exploitability

Present is not the same as exploitable

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Is a vulnerable build present?

Compare these published version ranges with your installed build and any vendor patches.

  1. Affected versionversion=>= 0.36.0, < 0.40.0

What conditions does exploitation require?

Attack vectornetwork
Required privilegesauthenticated

What is affected?

ControlPlane · Flux Operatorversion=>= 0.36.0, < 0.40.0

Published CVSS scores

5.3GitHub, Inc.CVSS:3.1/AV:N/AC:H/PR:L/UI:N/S:U/C:H/I:N/A:N

CVSS describes severity. EPSS estimates exploitation probability.

Attacks

What attackers are doing with it

Daily unique IPs observed by Shadowserver honeypots for known exploited vulnerabilities (KEVs). Missing observations do not establish an absence of attacks.

Daily unique IPsNo honeypot observations are available for this CVE in the selected window.

No observations available

Sep 10, 2026Sep 16, 2026
Latest reporting daySep 16, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectornetwork
Privilegesauthenticated
Known exploitationUnconfirmed
Public exploitUnconfirmed

Weakness, pattern, technique

CWE-862Missing Authorization
CWE-269Improper Privilege Management
T1190Exploit Public-Facing Application

Public exploit references

No public exploit references are available in this record.

Labels summarize the accepted research assessment. They do not indicate a test against your environment.

Technologies

Your stack

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Your stack

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