CVE-2025-24514 is a vulnerability classified under CWE-20 (Improper Input Validation) found in the Kubernetes ingress-nginx controller, specifically affecting versions from initial releases up to 1.12.0. The flaw exists in the handling of the `auth-url` annotation within Ingress resources, which is intended to configure external authentication for ingress traffic. Due to insufficient validation, an attacker with permissions to create or modify Ingress resources can inject arbitrary nginx configuration directives via this annotation. This injection can lead to arbitrary code execution within the ingress-nginx controller's runtime environment. Since the ingress-nginx controller typically runs with elevated privileges and has access to all Kubernetes Secrets cluster-wide by default, exploitation can also result in the disclosure of sensitive information such as credentials, tokens, and certificates. The vulnerability does not require user interaction and can be exploited remotely over the network, with only limited privileges needed to manipulate Ingress resources. The CVSS v3.1 score of 8.8 reflects the high impact on confidentiality, integrity, and availability, combined with low attack complexity and no user interaction. Although no public exploits have been reported yet, the potential for severe cluster compromise is significant. The vulnerability was publicly disclosed on March 24, 2025, and remediation involves upgrading ingress-nginx to a fixed version beyond 1.12.0 once available and applying strict RBAC policies to limit who can create or modify Ingress resources. Additionally, monitoring and auditing Ingress annotations for suspicious changes can help detect exploitation attempts.

For European organizations relying on Kubernetes clusters with ingress-nginx controllers, this vulnerability poses a critical risk. Successful exploitation can lead to full compromise of the ingress-nginx controller, enabling attackers to execute arbitrary code and gain access to all Kubernetes Secrets accessible by the controller. This can result in leakage of sensitive data, including credentials and certificates, potentially allowing lateral movement within the cluster and beyond. The integrity of ingress traffic routing can be undermined, causing denial of service or traffic interception. Given the widespread adoption of Kubernetes in Europe across sectors such as finance, healthcare, and government, the impact could be severe, including data breaches, service outages, and regulatory non-compliance under GDPR. The ease of exploitation with minimal privileges and no user interaction increases the threat level, especially in multi-tenant or shared cluster environments common in European cloud deployments.

1. Upgrade ingress-nginx to a version later than 1.12.0 where the vulnerability is patched as soon as such a release is available. 2. Implement strict Role-Based Access Control (RBAC) policies to restrict which users or service accounts can create or modify Ingress resources, minimizing the risk of malicious annotation injection. 3. Audit and monitor Ingress resource annotations regularly for unexpected or suspicious `auth-url` values or other configuration changes. 4. Use admission controllers or validating webhooks to enforce strict validation of Ingress annotations, rejecting any that do not conform to expected patterns. 5. Limit the privileges of the ingress-nginx controller itself where possible, for example by restricting its access to only necessary Secrets rather than cluster-wide access. 6. Employ network segmentation and zero-trust principles to reduce the blast radius if the ingress-nginx controller is compromised. 7. Maintain up-to-date backups and incident response plans specifically addressing Kubernetes cluster compromise scenarios. 8. Educate DevOps and security teams about this vulnerability and the importance of secure Ingress resource management.