CVE-2026-23990
5.3 · MEDIUMOverview
CVE-2026-23990 is a medium-severity vulnerability affecting control-plane flux_operator. It was published on January 21, 2026 and has a CVSS 3.1 base score of 5.3 (MEDIUM).
This vulnerability has a CVSS 3.1 base score of 5.3, rated MEDIUM. It can be exploited remotely over the network. Some level of privileges is required for exploitation.
Technical Description
The Flux Operator is a Kubernetes CRD controller that manages the lifecycle of CNCF Flux CD and the ControlPlane enterprise distribution. Starting in version 0.36.0 and prior to version 0.40.0, a privilege escalation vulnerability exists in the Flux Operator Web UI authentication code that allows an attacker to bypass Kubernetes RBAC impersonation and execute API requests with the operator's service account privileges. In order to be vulnerable, cluster admins must configure the Flux Operator with an OIDC provider that issues tokens lacking the expected claims (e.g., `email`, `groups`), or configure custom CEL expressions that can evaluate to empty values. After OIDC token claims are processed through CEL expressions, there is no validation that the resulting `username` and `groups` values are non-empty. When both values are empty, the Kubernetes client-go library does not add impersonation headers to API requests, causing them to be executed with the flux-operator service account's cr
Remediation
Check the references section for vendor advisories and patches from control-plane. Update flux_operator to the latest patched version. If immediate patching is not possible, review the CVSS vector to understand the attack surface and apply compensating controls such as network segmentation or access restrictions.
Affected Products
| Vendor | Product | Versions | Status |
|---|---|---|---|
| control-plane | flux_operator | >= 0.36.0, < 0.40.0 | Affected |
References
Frequently Asked Questions
What is CVE-2026-23990?
CVE-2026-23990 is a medium-severity vulnerability affecting control-plane flux_operator. It was published on January 21, 2026 and has a CVSS 3.1 base score of 5.3 (MEDIUM).
How severe is CVE-2026-23990?
This vulnerability has a CVSS 3.1 base score of 5.3, rated MEDIUM. It can be exploited remotely over the network. Some level of privileges is required for exploitation.
How do I fix or remediate CVE-2026-23990?
Check the references section for vendor advisories and patches from control-plane. Update flux_operator to the latest patched version. If immediate patching is not possible, review the CVSS vector to understand the attack surface and apply compensating controls such as network segmentation or access restrictions.
How can CyberStrike help with CVE-2026-23990?
CyberStrike's AI-powered security agents can automatically detect CVE-2026-23990 across your infrastructure using autonomous pentesting, DAST scanning, and HackBrowser. The platform continuously monitors for known vulnerabilities and provides actionable remediation guidance prioritized by real-world exploitability.
How CyberStrike Helps
AI agents map your attack surface to find vulnerabilities like this one.
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