CVE-2025-47282 in external-dns-management
Summary
by MITRE • 05/19/2025
Gardener External DNS Management is an environment to manage external DNS entries for a kubernetes cluster. A security vulnerability was discovered in Gardener's External DNS Management prior to version 0.23.6 that could allow a user with administrative privileges for a Gardener project or a user with administrative privileges for a shoot cluster, including administrative privileges for a single namespace of the shoot cluster, to obtain control over the seed cluster where the shoot cluster is managed. This CVE affects all Gardener installations no matter of the public cloud provider(s) used for the seed clusters/shoot clusters. The affected component is `gardener/external-dns-management`. The `external-dns-management` component may also be deployed on the seeds by the `gardener/gardener-extension-shoot-dns-service` extension when the extension is enabled. In this case, all versions of the `shoot-dns-service` extension `<= v1.60.0` are affected by this vulnerability. Version 0.23.6 of Gardener External DNS Management fixes the issue.
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Analysis
by VulDB Data Team • 05/19/2025
The vulnerability identified as CVE-2025-47282 affects the gardener/external-dns-management component within the Gardener Kubernetes management platform, representing a critical privilege escalation flaw that undermines cluster security boundaries. This vulnerability specifically targets the relationship between shoot clusters and their managing seed clusters, creating an attack vector that allows unauthorized users to escalate privileges and gain control over the seed cluster infrastructure. The flaw exists in versions prior to 0.23.6 of the external-dns-management component and additionally impacts the gardener/gardener-extension-shoot-dns-service extension versions up to v1.60.0, making it particularly widespread across Gardener installations regardless of the underlying public cloud provider implementation. The vulnerability's impact extends beyond simple access control issues as it fundamentally compromises the isolation between different cluster layers, creating potential for broader system compromise.
The technical mechanism behind this vulnerability stems from insufficient access controls and privilege validation within the external-dns-management component's handling of DNS entry management operations. When users possess administrative privileges for either a Gardener project or a shoot cluster, including namespace-level administrative rights, they can exploit this flaw to escalate their privileges to seed cluster level access. This occurs because the component fails to properly validate the security boundaries between different cluster management layers, allowing lateral movement from shoot cluster administration to seed cluster control. The vulnerability manifests through improper authorization checks that should prevent users from accessing seed cluster resources when they only have shoot cluster administrative privileges. This type of flaw aligns with CWE-285: Improper Authorization, which specifically addresses insufficient access control mechanisms that allow unauthorized users to perform privileged operations.
The operational impact of CVE-2025-47282 is severe and potentially catastrophic for organizations relying on Gardener for Kubernetes cluster management, as it enables attackers to gain control over the entire seed cluster infrastructure. This compromise allows malicious actors to manipulate DNS records across multiple shoot clusters, potentially enabling DNS hijacking, service disruption, or even complete control over the underlying cloud infrastructure. The vulnerability's widespread nature means that organizations using Gardener installations across multiple cloud providers are all at risk, as the flaw exists at the platform level rather than being specific to particular cloud implementations. The ability to control seed clusters provides attackers with access to multiple shoot clusters managed by that same seed, potentially creating a cascading effect that could compromise an entire organization's Kubernetes deployment infrastructure. This vulnerability directly maps to ATT&CK technique T1078.004: Valid Accounts - Cloud Accounts, as it allows privilege escalation through legitimate administrative accounts within the Gardener platform.
Organizations should immediately implement mitigation strategies to address this vulnerability by upgrading to Gardener version 0.23.6 or later, which contains the necessary fixes for the external-dns-management component. Additionally, administrators should review and tighten access controls for Gardener projects and shoot cluster administrative privileges, implementing the principle of least privilege to minimize the potential impact of compromised accounts. The gardener-extension-shoot-dns-service extension versions up to v1.60.0 should also be updated to ensure complete protection, as these older versions remain vulnerable to the same privilege escalation attack. Security monitoring should be enhanced to detect unusual DNS management activities that might indicate exploitation attempts, particularly around cross-cluster privilege escalation events. Regular security audits of Gardener configurations and access control policies are recommended to identify and remediate any additional potential weaknesses that could be exploited in conjunction with this vulnerability, ensuring comprehensive protection against both current and emerging threats in the Kubernetes cluster management ecosystem.