CVE-2025-30260 is a high-severity vulnerability affecting QNAP Systems Inc.'s Qsync Central product, specifically version 4.5.x.x. The vulnerability is classified under CWE-770, which pertains to the allocation of resources without limits or throttling. In this case, a remote attacker who has obtained a user account on the affected Qsync Central instance can exploit this flaw to consume or lock resources excessively. This resource exhaustion prevents other systems, applications, or processes from accessing the same type of resource, effectively causing a denial of service (DoS) condition. The vulnerability does not require user interaction and can be exploited remotely with low attack complexity and no privileges beyond a valid user account. The CVSS 4.0 base score is 7.1, reflecting its high severity, with the vector indicating network attack vector, low complexity, no user interaction, and high impact on availability. The vulnerability was fixed in Qsync Central version 4.5.0.7 released on April 23, 2025. No known exploits are currently reported in the wild. The root cause is the lack of resource allocation limits or throttling mechanisms, which allows an authenticated user to monopolize resources, leading to service degradation or outage for other legitimate users or processes relying on those resources.

For European organizations using QNAP Qsync Central 4.5.x.x, this vulnerability poses a significant risk to service availability. Qsync Central is often used for file synchronization and collaboration across distributed environments, so exploitation could disrupt business continuity by causing denial of service conditions. This can impact productivity, data synchronization reliability, and potentially lead to cascading failures in dependent systems. Organizations in sectors with high reliance on continuous data availability, such as finance, healthcare, and critical infrastructure, may face operational disruptions. Additionally, since exploitation requires only a valid user account, insider threats or compromised credentials could be leveraged to trigger the attack, increasing the risk profile. Although no known exploits are reported yet, the ease of exploitation and high impact on availability make this a critical concern for maintaining operational resilience in European enterprises.

European organizations should immediately verify their Qsync Central version and upgrade to version 4.5.0.7 or later to apply the official patch that addresses this vulnerability. Beyond patching, organizations should implement strict user account management policies, including multi-factor authentication (MFA) to reduce the risk of credential compromise. Monitoring resource usage patterns on Qsync Central servers can help detect abnormal resource consumption indicative of exploitation attempts. Network segmentation and access controls should be enforced to limit exposure of Qsync Central interfaces to only trusted networks and users. Additionally, implementing rate limiting or resource quotas at the application or system level can provide an additional layer of defense against resource exhaustion attacks. Regular auditing of user accounts and privileges will help identify and disable unnecessary or dormant accounts that could be exploited. Finally, organizations should prepare incident response plans specific to denial of service scenarios affecting Qsync Central services.