CVE-2025-57711 is a vulnerability identified in QNAP Systems Inc.'s Qsync Central software, specifically affecting version 5.0.x.x. The vulnerability is categorized as CWE-770, which involves allocation of resources without limits or throttling. This flaw allows a remote attacker who has already obtained administrator-level access to exploit the vulnerability by consuming resources excessively, thereby preventing other systems, applications, or processes from accessing the same resource type. This can lead to denial of service conditions within the affected environment. The vulnerability does not require user interaction but does require high privileges, limiting the attack vector to those with administrative access. The CVSS 4.0 base score is 3.6, reflecting a low severity primarily due to the prerequisite of administrative privileges and the limited impact scope. The vendor addressed this vulnerability in Qsync Central version 5.0.0.4, released on January 20, 2026. No public exploits have been reported, and the vulnerability was officially published on February 11, 2026. The issue primarily impacts availability by enabling resource exhaustion attacks that can disrupt normal operations of Qsync Central and dependent systems.

For European organizations, the primary impact of CVE-2025-57711 is on the availability of Qsync Central services. Organizations relying on Qsync Central for file synchronization and collaboration may experience denial of service conditions if an attacker with administrator access exploits this vulnerability to exhaust resources. This could disrupt business continuity, especially in sectors where timely file sharing and synchronization are critical, such as finance, healthcare, and manufacturing. The requirement for administrative privileges reduces the likelihood of widespread exploitation but elevates the risk if insider threats or compromised administrator accounts exist. Additionally, resource exhaustion could indirectly affect other applications or processes sharing the same resources, potentially amplifying operational disruptions. Given QNAP's popularity in small to medium enterprises and some larger organizations across Europe, the impact could be significant in environments where patching is delayed or administrative account security is weak.

1. Upgrade Qsync Central to version 5.0.0.4 or later immediately to apply the official patch addressing this vulnerability. 2. Enforce strict access controls and monitoring on administrator accounts to prevent unauthorized access, including multi-factor authentication and regular credential audits. 3. Implement resource usage monitoring and alerting on Qsync Central servers to detect unusual resource consumption patterns indicative of exploitation attempts. 4. Segment Qsync Central infrastructure from other critical systems to limit the impact of resource exhaustion on broader network operations. 5. Conduct regular security training for administrators to recognize and prevent potential insider threats or credential compromise. 6. Review and limit the number of users with administrative privileges to the minimum necessary. 7. Maintain up-to-date backups of critical data synchronized via Qsync to ensure recovery in case of service disruption.