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 issue stems from insufficient validation of the 'auth-url' annotation in Ingress resource definitions. This annotation is intended to specify an external authentication URL, but due to improper sanitization, an attacker with privileges to create or modify Ingress resources can inject arbitrary configuration directives into the nginx configuration generated by the ingress controller. This injection can lead to arbitrary code execution within the ingress-nginx controller's runtime environment. Additionally, because the ingress-nginx controller typically runs with permissions that allow it to access all Kubernetes Secrets cluster-wide, an attacker can leverage this flaw to disclose sensitive information stored as Secrets. The vulnerability has a CVSS v3.1 score of 8.8, indicating high severity, with attack vector being network-based, low attack complexity, requiring privileges but no user interaction, and impacting confidentiality, integrity, and availability. The flaw is critical because ingress-nginx is widely used in Kubernetes clusters to manage external access, and the ability to execute arbitrary code or access Secrets can lead to full cluster compromise. No patches were listed at the time of publication, and no known exploits have been reported in the wild, but the risk remains significant given the nature of the flaw and the typical permissions of the ingress controller.

For European organizations relying on Kubernetes with ingress-nginx for managing external traffic, this vulnerability poses a severe risk. Exploitation could lead to unauthorized access to sensitive data, including credentials and configuration secrets, potentially enabling lateral movement within the cluster and beyond. The arbitrary code execution capability could allow attackers to deploy malicious workloads, disrupt services, or exfiltrate data, impacting confidentiality, integrity, and availability of critical applications. Given the widespread adoption of Kubernetes in European enterprises and public sector organizations, especially in finance, healthcare, and government, the impact could be substantial. Regulatory compliance risks also arise due to potential data breaches involving personal or sensitive information protected under GDPR. The cluster-wide access to Secrets by the ingress controller amplifies the severity, as attackers could gain control over multiple services and data stores. Operational disruptions could lead to financial losses, reputational damage, and legal consequences.

European organizations should prioritize upgrading ingress-nginx to a version beyond 1.12.0 where this vulnerability is addressed once patches are available. Until then, strict RBAC policies should be enforced to limit who can create or modify Ingress resources, minimizing the risk of malicious annotation injection. Implement admission controllers or webhook policies to validate and sanitize Ingress annotations, especially 'auth-url', preventing unauthorized or malformed inputs. Restrict the permissions of the ingress-nginx controller to the minimum necessary, avoiding cluster-wide access to Secrets if possible, by employing Kubernetes Pod Security Policies or OPA Gatekeeper policies. Monitor ingress-nginx logs and Kubernetes audit logs for suspicious Ingress resource changes or anomalous behavior. Employ network segmentation and isolate critical clusters to reduce blast radius. Regularly review and rotate Secrets to limit exposure duration. Finally, maintain an incident response plan tailored for Kubernetes environments to quickly address potential exploitation.