Gardener: Authorization Bypass via Group Subject Injection

Gardener implements the automated management and operation of Kubernetes clusters as a service. Prior to 1.142.6, 1.143.3, 1.144.2, and 1.145.0, the customverbauthorizer admission plugin's mustCheckProjectMembers manage-members check compares changes to User subjects but does not account for Group or ServiceAccount subjects in Project.spec.members. A project administrator who lacks manage-members permission can add arbitrary Group or ServiceAccount subjects, including the system:authenticated Group, and thereby grant broad project access. The resulting access can include Shoots, Secrets, and cloud provider credentials. This issue is fixed in versions 1.142.6, 1.143.3, 1.144.2, and 1.145.0.

Gardener providers vulnerable to code injection when Terraformer is used for infrastructure provisioning

Project Gardener implements the automated management and operation of Kubernetes clusters as a service. Code injection may be possible in Gardener Extensions for AWS providers prior to version 1.64.0, Azure providers prior to version 1.55.0, OpenStack providers prior to version 1.49.0, and GCP providers prior to version 1.46.0. This vulnerability could allow a user with administrative privileges for a Gardener project to obtain control over the seed cluster where the shoot cluster is managed. This affects all Gardener installations where Terraformer is used/can be enabled for infrastructure provisioning with any of the affected components. This issue has been patched in Gardener Extensions for AWS providers version 1.64.0, Azure providers version 1.55.0, OpenStack providers version 1.49.0, and GCP providers version 1.46.0.

gardenctl is vulnerable to Command Injection when used with non‑POSIX shells

gardenctl is a command-line client for the Gardener which configures access to clusters and cloud provider CLI tools. When using non‑POSIX shells such as Fish and PowerShell, versions 2.11.0 and below of gardenctl allow an attacker with administrative privileges for a Gardener project to craft malicious credential values. The forged credential values are used in infrastructure Secret objects that break out of the intended string context when evaluated in Fish or PowerShell environments used by the Gardener service operators. This issue is fixed in version 2.12.0.

Bypassing project secret validation can lead to privilege escalation

Gardener implements the automated management and operation of Kubernetes clusters as a service. A security vulnerability was discovered in Gardener prior to versions 1.116.4, 1.117.5, 1.118.2, and 1.119.0 that could allow a user with administrative privileges for a Gardener project to obtain control over the seed cluster(s) where their shoot clusters are managed. This CVE affects all Gardener installations no matter of the public cloud provider(s) used for the seed clusters/shoot clusters. `gardener/gardener` (`gardenlet`) is the affected component. Versions 1.116.4, 1.117.5, 1.118.2, and 1.119.0 fix the issue.

Gardener vulnerable to metadata injection for a project secret that can lead to privilege escalation

Gardener implements the automated management and operation of Kubernetes clusters as a service. A security vulnerability was discovered in the `gardenlet` component of Gardener prior to versions 1.116.4, 1.117.5, 1.118.2, and 1.119.0. It could allow a user with administrative privileges for a Gardener project to obtain control over the seed cluster(s) where their shoot clusters are managed. This CVE affects all Gardener installations where gardener/gardener-extension-provider-gcp is in use. Versions 1.116.4, 1.117.5, 1.118.2, and 1.119.0 fix the issue.

In Gardener before 0.20.0, incorrect access control in seed clusters allows information disclosure by sending HTTP GET requests from one's own shoot clusters to foreign shoot clusters. This occurs because traffic from shoot to seed via the VPN endpoint is not blocked.

Following the Gardener architecture, the Kubernetes apiserver of a Gardener managed shoot cluster resides in the corresponding seed cluster. Due to missing network isolation a shoot's apiserver can access services/endpoints in the private network of its corresponding seed cluster. Combined with other minor Kubernetes security issues, the missing network isolation theoretically can lead to compromise other shoot or seed clusters in the "Gardener" context. The issue is rated high due to the high impact of a potential exploitation in "Gardener" context. This was fixed in Gardener release 0.12.4.