CVE-2025-59952 is a vulnerability classified under CWE-20 (Improper Input Validation) and CWE-94 (Improper Control of Generation of Code) affecting the minio-java SDK, a widely used client for Amazon S3 compatible object storage services. In versions prior to 8.6.0, the SDK automatically performs substitution of XML tag values that reference system properties or environment variables with their actual runtime values during XML processing. This behavior occurs without proper validation or sanitization of the XML input, allowing an attacker who can supply crafted XML content to cause the SDK to disclose sensitive system information embedded in environment variables or system properties. Such information may include credentials, file paths, or configuration details that could facilitate further attacks or unauthorized access. The vulnerability is remotely exploitable without requiring authentication or user interaction, increasing its risk profile. The CVSS 4.0 base score of 8.7 reflects the high impact on confidentiality with no required privileges or interaction, and low attack complexity. The flaw was addressed in minio-java version 8.6.0 by disabling automatic substitution of system properties and environment variables in XML tag values, thus preventing unintended information leakage. Although no active exploits have been reported, the vulnerability poses a significant risk to any service or application using affected minio-java versions to interact with S3-compatible storage, especially in environments processing untrusted XML data inputs.

For European organizations, the impact of CVE-2025-59952 can be substantial, particularly for those leveraging minio-java SDK in cloud storage solutions or hybrid cloud environments. The vulnerability can lead to unauthorized disclosure of sensitive information such as credentials, internal file paths, and system configurations, which can be leveraged by attackers to escalate privileges, move laterally within networks, or exfiltrate data. This exposure undermines confidentiality and potentially integrity of critical systems. Organizations in sectors with strict data protection regulations, such as finance, healthcare, and government, face increased compliance risks and potential reputational damage if sensitive data is leaked. Additionally, the vulnerability’s remote exploitability without authentication increases the attack surface, especially for public-facing applications or services processing XML data from external sources. The lack of known exploits in the wild currently provides a window for proactive mitigation, but the high CVSS score indicates that exploitation could have severe consequences if weaponized.

European organizations should immediately upgrade all instances of minio-java SDK to version 8.6.0 or later to eliminate the vulnerability. For environments where immediate upgrade is not feasible, implement strict input validation and sanitization on all XML data received from untrusted sources before processing with minio-java. Employ network segmentation and access controls to limit exposure of services using the vulnerable SDK to trusted networks only. Monitor logs and network traffic for unusual XML payloads or unexpected system property references that could indicate exploitation attempts. Conduct regular security audits and code reviews focusing on third-party dependencies like minio-java to identify and remediate similar risks proactively. Additionally, update incident response plans to include scenarios involving sensitive data exposure through SDK vulnerabilities. Finally, maintain awareness of vendor advisories and threat intelligence feeds for any emerging exploit activity related to this CVE.