CVE-2025-47211 is a path traversal vulnerability (CWE-22) affecting QNAP Systems Inc.'s QTS operating system, specifically versions 5.2.x prior to 5.2.6.3195 build 20250715. This vulnerability allows a remote attacker who has already obtained administrator-level credentials to exploit the flaw to read arbitrary files on the system outside of the intended directory scope. Path traversal vulnerabilities occur when user input is not properly sanitized, enabling attackers to manipulate file paths and access sensitive files such as configuration files, password stores, or system data that should be protected. The vulnerability does not require user interaction and can be exploited remotely over the network. The CVSS 4.0 base score is 6.9 (medium severity), reflecting that the attack vector is network-based, with low attack complexity, no privileges required beyond administrator access, and no user interaction needed. The impact is primarily on confidentiality, as the attacker can read sensitive files, but it does not affect integrity or availability. QNAP has addressed this vulnerability in QTS and QuTS hero versions 5.2.6.3195 build 20250715 and later. There are no known exploits in the wild at the time of publication. The vulnerability was reserved in May 2025 and published in October 2025.

For European organizations using QNAP NAS devices running vulnerable QTS versions, this vulnerability poses a significant confidentiality risk. Attackers with administrator credentials could access sensitive files, including potentially critical system configurations, user data, or credentials stored on the device. This could lead to data breaches, intellectual property theft, or further compromise of internal networks if attackers leverage the information obtained. Since QNAP devices are commonly used in small to medium enterprises, educational institutions, and some government agencies across Europe for storage and backup, the exposure could be widespread. The requirement for administrator access limits the risk to scenarios where credentials are compromised or insider threats exist. However, given the critical role of NAS devices in data storage and backup, unauthorized file access could disrupt business continuity and regulatory compliance, especially under GDPR, which mandates strict data protection controls. The absence of known exploits reduces immediate risk but does not eliminate the threat, as attackers may develop exploits post-disclosure.

European organizations should prioritize updating QNAP QTS and QuTS hero systems to version 5.2.6.3195 build 20250715 or later to remediate this vulnerability. Beyond patching, organizations should enforce strong administrator credential policies, including multi-factor authentication (MFA), to reduce the risk of credential compromise. Regular auditing of administrator account activity and access logs can help detect suspicious behavior early. Network segmentation should be applied to limit access to QNAP devices only to trusted management networks and authorized personnel. Additionally, organizations should implement strict file access monitoring and alerting on NAS devices to identify unauthorized file access attempts. Backup strategies should be reviewed to ensure data integrity and availability in case of compromise. Finally, organizations should consider disabling or restricting remote administration interfaces if not required, reducing the attack surface.