Flux Operator Web UI Impersonation Bypass via Empty OIDC Claims

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.

CVSS:3.1/AV:N/AC:H/PR:L/UI:N/S:U/C:H/I:N/A:N

特权管理不恰当

flux-operator 安全漏洞

flux-operator是ControlPlane Enterprise for Flux CD开源的一个生命周期管理软件。 flux-operator 0.36.0版本至0.40.0之前版本存在安全漏洞，该漏洞源于Web UI身份验证代码未验证生成的username和groups值是否为空，可能导致权限提升。

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