CVE-2025-47284: Gardener Privilege Escalation Vulnerability

CVE-2025-47284 Overview

A critical privilege escalation vulnerability has been discovered in the gardenlet component of Gardener, an open-source platform that implements automated management and operation of Kubernetes clusters as a service. This security flaw allows a user with administrative privileges for a Gardener project to obtain control over the seed cluster(s) where their shoot clusters are managed, potentially compromising the entire Kubernetes infrastructure.

Critical Impact

This vulnerability enables complete seed cluster takeover from a project administrator position, affecting all Gardener installations using the gardener/gardener-extension-provider-gcp extension.

Affected Products

• Gardener versions prior to 1.116.4
• Gardener versions prior to 1.117.5
• Gardener versions prior to 1.118.2 and 1.119.0

Discovery Timeline

• 2025-05-19 - CVE-2025-47284 published to NVD
• 2025-09-04 - Last updated in NVD database

Technical Details for CVE-2025-47284

Vulnerability Analysis

This vulnerability affects the gardenlet component, which is responsible for managing the lifecycle of shoot clusters on seed clusters within the Gardener ecosystem. The flaw allows privilege escalation from a Gardener project administrator to gain unauthorized control over seed clusters.

The attack can be performed remotely over the network and requires only low-level privileges (project administrator access) to exploit. No user interaction is required, and the scope is changed, meaning the vulnerability can affect resources beyond its initial security scope. The impact on confidentiality, integrity, and availability is rated as high, indicating that an attacker could gain complete control over seed cluster resources.

This vulnerability is classified under CWE-150, which relates to improper neutralization of escape, meta, or control sequences. In this context, the vulnerability may involve improper handling of input that allows an attacker to escape their intended privilege boundary within the Gardener platform.

Root Cause

The root cause lies in insufficient access control validation within the gardenlet component. When processing requests from Gardener project administrators, the component fails to properly restrict operations that could affect seed cluster resources outside the project's intended scope. This allows a malicious project administrator to break out of their project isolation and gain control over the underlying seed infrastructure.

Attack Vector

The attack is executed remotely over the network by an authenticated user with Gardener project administrator privileges. The attacker leverages their legitimate project access to exploit the improper boundary enforcement in the gardenlet component, escalating their privileges to gain control over seed clusters.

All Gardener installations where gardener/gardener-extension-provider-gcp is in use are affected. For detailed technical information about the vulnerability mechanism, refer to the GitHub Security Advisory.

Detection Methods for CVE-2025-47284

Indicators of Compromise

• Unusual API requests from project administrators targeting seed cluster resources
• Unexpected modifications to seed cluster configurations or credentials
• Anomalous gardenlet activity logs showing cross-project or cross-seed operations

Detection Strategies

• Monitor Gardener API audit logs for project administrators attempting to access or modify seed cluster resources
• Implement alerts for unexpected privilege changes or role bindings within seed clusters
• Review gardenlet logs for operations that cross project boundaries

Monitoring Recommendations

• Enable comprehensive audit logging for all Gardener API operations
• Implement real-time alerting on seed cluster configuration changes
• Monitor for unauthorized credential access or secret enumeration in seed namespaces

How to Mitigate CVE-2025-47284

Immediate Actions Required

• Upgrade Gardener to a patched version immediately (1.116.4, 1.117.5, 1.118.2, or 1.119.0)
• Review audit logs to identify any potential exploitation attempts
• Audit project administrator access and permissions across all Gardener projects
• Verify integrity of seed cluster configurations and credentials

Patch Information

The Gardener project has released patched versions that address this vulnerability:

Organizations should upgrade to the appropriate patched version based on their current deployment branch. Refer to the GitHub Security Advisory for additional details.

Workarounds

• Temporarily restrict project administrator privileges until patches can be applied
• Implement additional network segmentation between project and seed cluster components
• Enable enhanced audit logging and monitoring to detect potential exploitation attempts
• Consider temporarily disabling the gardener-extension-provider-gcp extension if not critical to operations