CVE-2025-62853 is a path traversal vulnerability classified under CWE-22 affecting QNAP Systems Inc.'s File Station 5 software, specifically versions 5.5.x before 5.5.6.5166. Path traversal vulnerabilities occur when an application improperly sanitizes user-supplied file path inputs, allowing attackers to access files and directories outside the intended scope. In this case, an attacker who has already obtained a valid user account on the QNAP NAS device can exploit the vulnerability to read arbitrary files on the system. This can lead to unauthorized disclosure of sensitive information such as configuration files, credentials, or other critical system data. The vulnerability is exploitable remotely over the network without requiring user interaction, but it does require the attacker to have low-level privileges (a user account). The CVSS v4.0 score is 5.2 (medium severity), reflecting the moderate impact on confidentiality and integrity, with no impact on availability. The vulnerability has been addressed in File Station 5 version 5.5.6.5166 and later, and users are strongly advised to upgrade. No known exploits have been reported in the wild, but the presence of a valid user account prerequisite means insider threats or compromised credentials could be leveraged to exploit this flaw.

For European organizations, this vulnerability poses a risk of unauthorized data disclosure if attackers gain user credentials, which could happen through phishing, credential stuffing, or insider threats. Sensitive corporate or personal data stored on QNAP NAS devices could be exposed, potentially leading to data breaches, compliance violations (e.g., GDPR), and reputational damage. Organizations relying on QNAP NAS for critical file storage, backup, or sharing services may face increased risk of information leakage. The vulnerability does not allow remote code execution or denial of service, limiting its impact to confidentiality and integrity. However, given the widespread use of QNAP devices in SMBs and enterprises across Europe, especially in sectors like finance, healthcare, and government, the potential for sensitive data exposure is significant. The lack of known exploits in the wild reduces immediate risk but does not eliminate the threat, especially if attackers develop exploits targeting this vulnerability.

European organizations using QNAP File Station 5 should immediately upgrade to version 5.5.6.5166 or later to remediate this vulnerability. In addition to patching, organizations should enforce strong user authentication policies, including multi-factor authentication (MFA), to reduce the risk of credential compromise. Regularly auditing user accounts and permissions on QNAP devices can help identify and remove unnecessary or dormant accounts that could be exploited. Network segmentation should be applied to limit access to NAS management interfaces to trusted internal networks or VPNs. Monitoring and logging access to File Station can help detect suspicious activities indicative of exploitation attempts. Organizations should also educate users on phishing and credential hygiene to prevent account compromise. Finally, implementing file integrity monitoring on critical NAS files can alert administrators to unauthorized access or changes.