CVE-2025-59952 is a vulnerability identified in the minio-java SDK, a widely used client library for interacting with Amazon S3-compatible object storage services. Versions prior to 8.6.0 improperly handle XML input by automatically substituting XML tag values that reference system properties or environment variables with their actual runtime values. This behavior stems from inadequate input validation (CWE-20) and unsafe evaluation of XML content (related to CWE-94, code injection). When an attacker supplies crafted XML containing references to environment variables or system properties, the SDK processes these references and replaces them with sensitive data such as credentials, file paths, or system configuration details. Because the substitution occurs automatically without proper sanitization or restrictions, it can lead to unintended information disclosure. The vulnerability is exploitable remotely without requiring authentication or user interaction, increasing its risk profile. The CVSS 4.0 base score is 8.7 (high), reflecting the network attack vector, low attack complexity, no privileges or user interaction needed, and high confidentiality impact. The flaw is fixed in minio-java version 8.6.0 by disabling or properly handling such substitutions during XML processing. No known exploits are currently reported in the wild, but the potential impact on confidentiality is significant, especially for applications relying on minio-java for secure storage operations.

For European organizations, this vulnerability poses a significant risk of sensitive data exposure, including credentials and system configuration details, which could lead to further compromise of cloud storage environments or internal systems. Organizations using minio-java SDK in their cloud-native applications, microservices, or storage management tools may inadvertently expose secrets or configuration data to attackers able to supply malicious XML input. This could facilitate lateral movement, privilege escalation, or data exfiltration within enterprise networks. The vulnerability affects confidentiality primarily, but indirectly could impact integrity and availability if attackers leverage exposed credentials to manipulate stored data or disrupt services. Given the widespread adoption of S3-compatible storage solutions across Europe, especially in sectors like finance, healthcare, and government, the risk is amplified. Compliance with GDPR and other data protection regulations also means that data leaks resulting from this vulnerability could lead to regulatory penalties and reputational damage.

European organizations should immediately upgrade all instances of minio-java SDK to version 8.6.0 or later to eliminate the vulnerability. Where immediate upgrading is not feasible, organizations should implement strict input validation and sanitization on all XML content processed by applications using minio-java, ensuring that untrusted XML data cannot contain references to system properties or environment variables. Network-level controls such as Web Application Firewalls (WAFs) can be configured to detect and block suspicious XML payloads containing such references. Additionally, organizations should audit their codebases and configurations to identify any usage of minio-java SDK and assess exposure to untrusted XML inputs. Monitoring and logging should be enhanced to detect unusual access patterns or data exfiltration attempts related to storage services. Finally, secrets and credentials should be rotated regularly to limit the impact of any potential exposure.