CVE-2025-62856 is a path traversal vulnerability classified under CWE-22, impacting QNAP Systems Inc.'s File Station 5 software, specifically versions 5.5.x before 5.5.6.5190. The vulnerability allows a local attacker who has already obtained administrator-level access on the device to exploit the flaw to read files outside the permitted directories. This is achieved by manipulating file path inputs to traverse directories, bypassing normal access controls. The vulnerability does not require user interaction and can be exploited remotely only if the attacker has local admin privileges, which limits the attack surface. The CVSS 4.0 base score is 1.3, indicating low severity due to the prerequisite of administrative access and limited confidentiality impact (VC:L). The vulnerability does not affect integrity or availability. No evidence of active exploitation in the wild has been reported to date. The vendor has released a fix in File Station 5 version 5.5.6.5190 and later, which properly sanitizes and validates file path inputs to prevent directory traversal. Organizations running vulnerable versions should apply this update promptly to mitigate risk. Given that QNAP NAS devices are widely used for file storage and sharing, unauthorized file access could expose sensitive corporate or personal data if exploited.

For European organizations, the primary impact of this vulnerability is unauthorized disclosure of sensitive files stored on QNAP NAS devices running vulnerable File Station 5 versions. Although exploitation requires local administrator privileges, which reduces the likelihood of external attackers exploiting it directly, insider threats or attackers who have already compromised admin credentials could leverage this flaw to escalate data access. This could lead to exposure of confidential business documents, personal data protected under GDPR, or system configuration files, potentially facilitating further attacks or compliance violations. The vulnerability does not directly affect system integrity or availability, so operational disruption is unlikely. However, the breach of confidentiality could damage organizational reputation and result in regulatory penalties. Organizations relying heavily on QNAP NAS for critical data storage, especially in sectors like finance, healthcare, and government, should consider this vulnerability a risk to data confidentiality and prioritize patching. The lack of known exploits in the wild reduces immediate urgency but does not eliminate future risk.

1. Immediately upgrade File Station 5 to version 5.5.6.5190 or later, as this patch addresses the path traversal vulnerability by properly validating file paths. 2. Restrict administrative access to QNAP NAS devices to trusted personnel only, employing strong authentication methods such as multi-factor authentication (MFA) to reduce risk of credential compromise. 3. Monitor and audit administrator account activities on NAS devices to detect any unusual file access patterns that may indicate exploitation attempts. 4. Implement network segmentation to limit local access to NAS devices, reducing the attack surface for potential local attackers. 5. Regularly review and update access control policies on NAS shares to ensure least privilege principles are enforced. 6. Maintain up-to-date backups of critical data to mitigate potential data exposure or loss. 7. Educate administrators on the risks of path traversal vulnerabilities and the importance of applying security patches promptly. 8. Consider deploying endpoint detection and response (EDR) solutions to detect suspicious activities related to file access on NAS devices.