CVE-2025-47284 is a critical security vulnerability affecting the Gardener project, specifically the 'gardenlet' component responsible for managing Kubernetes clusters as a service. Gardener automates the operation and lifecycle management of Kubernetes clusters, organizing them into 'shoot' clusters (user clusters) managed via 'seed' clusters (infrastructure clusters). This vulnerability arises from improper neutralization of escape, meta, or control sequences (CWE-150) in the gardenlet component, which can be exploited by a user with administrative privileges on a Gardener project. Such a user could leverage this flaw to escalate their control from their shoot clusters to the underlying seed clusters. The seed clusters typically have broader privileges and control over multiple shoot clusters, making this a significant privilege escalation vector. The vulnerability affects all Gardener installations using the gardener-extension-provider-gcp extension prior to versions 1.116.4, 1.117.5, 1.118.2, and 1.119.0, which contain the necessary patches. The CVSS v3.0 base score is 9.9, indicating a critical severity with network attack vector, low attack complexity, requiring privileges but no user interaction, and impacting confidentiality, integrity, and availability with scope change. No known exploits are currently reported in the wild, but the potential impact is severe given the control over seed clusters. This vulnerability highlights the risks in multi-tenant Kubernetes management platforms where administrative privileges in one domain can lead to broader infrastructure compromise if input sanitization is insufficient.

For European organizations utilizing Gardener for Kubernetes cluster management, this vulnerability poses a significant risk. Compromise of seed clusters could lead to unauthorized access and control over multiple shoot clusters, potentially exposing sensitive data, disrupting critical workloads, or enabling lateral movement within cloud infrastructure. Organizations relying on Google Cloud Platform (GCP) as the infrastructure provider (given the gardener-extension-provider-gcp involvement) are particularly at risk. The breach of seed clusters could affect confidentiality by exposing tenant data, integrity by allowing malicious modifications to cluster configurations or workloads, and availability by disrupting cluster operations. Given the critical nature of Kubernetes in modern cloud-native deployments, this vulnerability could impact sectors such as finance, healthcare, telecommunications, and government services across Europe. The multi-tenant nature of Gardener means that a single compromised project admin could affect other tenants or services sharing the seed cluster, amplifying the impact. Additionally, the vulnerability could undermine trust in managed Kubernetes services and complicate compliance with European data protection regulations such as GDPR if data leakage occurs.

European organizations should immediately verify their Gardener versions and upgrade to the patched releases: 1.116.4, 1.117.5, 1.118.2, or 1.119.0 or later. It is critical to audit and restrict administrative privileges within Gardener projects to minimize the risk of privilege escalation. Implement strict role-based access controls (RBAC) to ensure that only trusted users have administrative rights. Conduct thorough input validation and sanitization reviews in any custom extensions or integrations with Gardener to prevent injection of escape or control sequences. Monitor seed cluster activity for anomalous behavior indicative of privilege escalation attempts. Employ network segmentation and isolate seed clusters from less trusted environments to limit lateral movement. Regularly review and update Kubernetes and Gardener security configurations, and consider deploying runtime security tools that can detect suspicious cluster management operations. Finally, maintain an incident response plan tailored to Kubernetes environments to quickly contain and remediate any exploitation attempts.