Tag: gardener

Overview

On May 19, 2025, a critical security vulnerability was published under the identifier CVE-2025-47284, affecting the Gardener project—a tool used for the automated management of Kubernetes clusters as a service. The issue resides in the gardenlet component and poses a serious risk of privilege escalation due to improper handling of metadata injection.

What is Gardener?

Gardener is an open-source project developed by SAP that provides Kubernetes-as-a-Service by automating the provisioning and operation of Kubernetes clusters. It uses a control plane for each managed cluster and supports multi-cloud environments. A component called gardenlet is deployed on seed clusters to manage shoot clusters on behalf of users.

Vulnerability Details

The vulnerability arises from improper neutralization of escape, meta, or control sequences, classified as CWE-150. Specifically, metadata injection into project secrets can be exploited by an attacker with administrative privileges over a Gardener project. This enables the attacker to escalate their privileges and gain control over the seed clusters that host the shoot clusters for that project.

All Gardener installations using the gardener/gardener-extension-provider-gcp module are affected.

Technical Impact

• CVSS v3.0 Score: 9.9 (Critical)
• Attack Vector: Network
• Attack Complexity: Low
• Privileges Required: Low
• User Interaction: None
• Scope: Changed
• Confidentiality, Integrity, and Availability Impact: High

The vulnerability can be exploited remotely over the network and requires only low-level privileges within the Gardener project. No user interaction is required. Once exploited, the attacker can manipulate critical cluster management operations and compromise the integrity and availability of managed Kubernetes environments.

Affected Versions

• Gardener versions < 1.116.4
• Gardener 1.117.0 to < 1.117.5
• Gardener 1.118.0 to < 1.118.2

Versions 1.116.4, 1.117.5, 1.118.2, and 1.119.0 contain patches addressing this issue.

Mitigation

It is strongly recommended that users upgrade to the latest patched versions of Gardener as listed above. Immediate action is required for any deployments using the vulnerable gardener-extension-provider-gcp module.

Conclusion

CVE-2025-47284 underscores the importance of secure metadata handling in cloud-native platforms. With a near-maximum CVSS score and the potential for full cluster compromise, this flaw should be addressed promptly by all affected users. For more details, refer to the GitHub security advisory.

Overview

On May 19, 2025, a critical vulnerability was disclosed in the Gardener Kubernetes cluster management platform. Identified as CVE-2025-47283, the flaw permits privilege escalation by bypassing project secret validation, potentially allowing a project administrator to gain unauthorized access to the seed cluster(s) responsible for managing shoot clusters.

This vulnerability is tracked under GHSA-3hw7-qj9h-r835 and has been rated as Critical with a CVSS v3.0 base score of 9.9.

Technical Details

The vulnerability stems from improper input validation, categorized under CWE-20: Improper Input Validation. This means that user-supplied data is not properly checked before being processed, allowing potentially malicious input to influence system behavior.

In the context of Gardener, an administrative user within a project could manipulate secrets associated with their cluster to influence the behavior of the gardenlet component running on the seed cluster. This manipulation enables them to elevate privileges and execute operations outside their intended scope.

Impact

This flaw impacts all Gardener installations regardless of the public cloud provider used for the seed or shoot clusters. Exploitation could allow:

• Unauthorized control over seed clusters
• Compromise of other tenant clusters
• Loss of confidentiality, integrity, and availability within the Kubernetes management infrastructure

The vulnerability has a Changed Scope in the CVSS vector, indicating that an attacker’s access could impact components beyond the initially vulnerable system.

Affected Versions

The following versions of gardener/gardener are affected:

• All versions prior to 1.116.4
• Versions 1.117.0 through 1.117.4
• Versions 1.118.0 through 1.118.1

Mitigation

Users are strongly advised to upgrade to one of the following patched versions:

• 1.116.4
• 1.117.5
• 1.118.2
• 1.119.0 or later

Upgrading ensures that project secret validation is enforced correctly, preventing unauthorized privilege escalation within the system.

Understanding the Terms

Gardener is an open-source project developed by SAP that enables the automated management of Kubernetes clusters at scale. It introduces the concept of shoot clusters (end-user Kubernetes clusters) and seed clusters (infrastructure clusters that host shoot clusters).

CVSS (Common Vulnerability Scoring System) provides a numerical score to indicate the severity of a vulnerability. A score of 9.9 indicates an extremely high risk, especially when no user interaction is required and the attack can be performed remotely.

CWE-20 represents a category of vulnerabilities arising from improper input validation, a common flaw that can lead to injection, escalation, or arbitrary code execution.

Conclusion

CVE-2025-47283 highlights the importance of strict input validation and the risks posed by misconfigured secrets in Kubernetes management platforms. Organizations using Gardener should patch immediately and review their cluster access policies to ensure secure multi-tenancy.