CVE-2025-54147 is a vulnerability classified under CWE-476 (NULL Pointer Dereference) affecting QNAP Systems Inc.'s Qsync Central software, specifically versions 5.0.x.x. The flaw arises when the software dereferences a NULL pointer, which can lead to a denial-of-service (DoS) condition by crashing the affected service or causing it to become unresponsive. Exploitation requires the attacker to have a valid user account on the system, but no further privileges or user interaction are necessary. The vulnerability is remotely exploitable over the network, making it accessible to attackers who can authenticate as users. The CVSS v4.0 score is 1.3, indicating low severity due to the limited impact (availability only), the requirement for a user account, and the absence of privilege escalation or confidentiality/integrity impact. The vendor has addressed the issue in Qsync Central version 5.0.0.4 released on January 20, 2026. No public exploits or active exploitation campaigns have been reported. The vulnerability primarily affects availability by enabling attackers to disrupt synchronization services, potentially impacting business continuity for organizations relying on Qsync Central for file synchronization and sharing.

For European organizations, the primary impact of CVE-2025-54147 is the potential disruption of Qsync Central services, which could lead to temporary denial of access to synchronized files and data. This may affect business operations, especially in sectors relying heavily on file synchronization for collaboration and data availability, such as finance, healthcare, and government. Although the vulnerability does not compromise confidentiality or integrity, the availability impact could result in operational delays and reduced productivity. Organizations with remote or distributed workforces using Qsync Central may experience increased downtime or require manual intervention to restore services. The low severity and requirement for authenticated access limit the threat scope, but insider threats or compromised user accounts could be leveraged to exploit this vulnerability. No known active exploitation reduces immediate risk, but unpatched systems remain vulnerable to potential future attacks.

European organizations should promptly upgrade Qsync Central to version 5.0.0.4 or later to remediate the vulnerability. In addition to patching, organizations should enforce strong user account security measures, including multi-factor authentication (MFA) to reduce the risk of account compromise. Regularly audit user accounts and permissions to ensure only authorized personnel have access to Qsync Central. Implement network segmentation to limit access to Qsync Central services from untrusted networks. Monitor logs for unusual activity indicative of attempted exploitation or account misuse. Employ intrusion detection systems (IDS) to detect anomalous behavior targeting Qsync Central. Establish incident response procedures to quickly address any service disruptions caused by exploitation attempts. Finally, maintain up-to-date backups of synchronized data to minimize operational impact in case of service outages.