Improper Privilege Management Affecting flux-operator package, versions <0.40.0-r0
Threat Intelligence
The probability is the direct output of the EPSS model, and conveys an overall sense of the threat of exploitation in the wild. The percentile measures the EPSS probability relative to all known EPSS scores. Note: This data is updated daily, relying on the latest available EPSS model version. Check out the EPSS documentation for more details.
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Start learning- Snyk IDSNYK-WOLFILATEST-FLUXOPERATOR-15385040
- published4 Mar 2026
- disclosed21 Jan 2026
Introduced: 21 Jan 2026
CVE-2026-23990 (opens in a new tab)How to fix?
Upgrade Wolfi flux-operator to version 0.40.0-r0 or higher.
NVD Description
Note: Versions mentioned in the description apply only to the upstream flux-operator package and not the flux-operator package as distributed by Wolfi.
See How to fix? for Wolfi relevant fixed versions and status.
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 credentials instead of the authenticated user's limited permissions. This can result in privilege escalation, data exposure, and/or information disclosure. Version 0.40.0 patches the issue.
References
- https://github.com/controlplaneio-fluxcd/flux-operator/commit/084540424f6de8ba5d88fb1fd1e8472ba29afd7e
- https://github.com/controlplaneio-fluxcd/flux-operator/pull/610
- https://github.com/controlplaneio-fluxcd/flux-operator/releases/tag/v0.40.0
- https://github.com/controlplaneio-fluxcd/flux-operator/security/advisories/GHSA-4xh5-jcj2-ch8q