CVE-2025-47282 is a critical security vulnerability identified in the Gardener External DNS Management component, a system used to manage external DNS entries for Kubernetes clusters. The vulnerability is classified under CWE-20, indicating improper input validation. It affects all versions of Gardener External DNS Management prior to 0.23.6 and also impacts the gardener-extension-shoot-dns-service extension versions up to 1.60.0 when enabled. The flaw allows users with administrative privileges at the Gardener project level or shoot cluster level—including those with admin rights limited to a single namespace—to escalate their control to the seed cluster, which manages the shoot clusters. This escalation is significant because seed clusters typically have broader control and access to multiple shoot clusters, representing a higher trust and privilege level within the Gardener architecture. The vulnerability is exploitable remotely (AV:N), requires low attack complexity (AC:L), and only requires privileges (PR:L) but no user interaction (UI:N). The scope is changed (S:C), meaning the vulnerability affects resources beyond the initially compromised component. The impact is severe across confidentiality, integrity, and availability (all rated high). Exploiting this vulnerability could allow an attacker to fully compromise the seed cluster, potentially leading to widespread disruption or control over multiple Kubernetes clusters managed by Gardener. No known exploits are currently reported in the wild, but the high CVSS score of 9.9 underscores the critical nature of this issue. The vulnerability is independent of the underlying public cloud provider, affecting all Gardener installations regardless of deployment environment. The issue was publicly disclosed on May 19, 2025, and fixed in version 0.23.6 of the external-dns-management component.

For European organizations utilizing Gardener for Kubernetes cluster management, this vulnerability poses a significant risk. The ability for a user with limited administrative privileges to escalate control to the seed cluster could lead to full compromise of multiple Kubernetes clusters, exposing sensitive data, disrupting services, and potentially enabling lateral movement within the organization's cloud infrastructure. Given the widespread adoption of Kubernetes and the growing use of Gardener in cloud-native environments, especially among enterprises and cloud service providers in Europe, the impact could be extensive. Organizations relying on Gardener for multi-cloud or hybrid cloud Kubernetes management may face increased risk of data breaches, service outages, and compliance violations, particularly under stringent EU data protection regulations such as GDPR. The vulnerability's independence from cloud providers means that organizations using AWS, Azure, Google Cloud, or private clouds with Gardener are all at risk. Additionally, the critical nature of the vulnerability could attract threat actors aiming for high-value targets, including financial institutions, government agencies, and critical infrastructure operators in Europe.

European organizations should immediately assess their Gardener deployments to determine if they are running vulnerable versions of external-dns-management (<0.23.6) or the shoot-dns-service extension (<=1.60.0). The primary mitigation is to upgrade these components to the fixed versions (external-dns-management 0.23.6 or later and shoot-dns-service extension >1.60.0). Beyond patching, organizations should enforce strict role-based access control (RBAC) policies to limit administrative privileges within Gardener projects and shoot clusters, minimizing the number of users with such rights. Implementing network segmentation and zero-trust principles around seed clusters can reduce the blast radius if a compromise occurs. Monitoring and logging of administrative actions within Gardener should be enhanced to detect anomalous behavior indicative of privilege escalation attempts. Regular security audits and penetration testing focusing on Kubernetes cluster management components are recommended. Additionally, organizations should consider isolating seed clusters and applying additional authentication mechanisms such as multi-factor authentication (MFA) for administrative access. Finally, maintaining an up-to-date inventory of Kubernetes management components and their versions will facilitate rapid response to future vulnerabilities.