CVE-2025-30275 is a vulnerability identified in QNAP Systems Inc.'s Qsync Central product, specifically a NULL pointer dereference issue categorized under CWE-476. This vulnerability affects versions 4.5.x.x of Qsync Central prior to 4.5.0.7, which was released on April 23, 2025. The flaw allows a remote attacker who has already obtained a user account on the system to exploit the vulnerability and trigger a denial-of-service (DoS) condition. The vulnerability arises when the software attempts to dereference a pointer that is NULL, leading to a crash or service disruption. The CVSS 4.0 base score is 5.3, indicating a medium severity level. The attack vector is network-based (AV:N), requiring low attack complexity (AC:L), no user interaction (UI:N), and privileges at the user level (PR:L). The vulnerability does not impact confidentiality, integrity, or availability beyond the DoS effect, and there is no scope change. No known exploits are currently reported in the wild. The vulnerability was responsibly disclosed and fixed in version 4.5.0.7 of Qsync Central.

For European organizations using QNAP Qsync Central, this vulnerability poses a risk of service disruption through denial-of-service attacks. Since exploitation requires an attacker to have a valid user account, the threat is primarily to environments where user credentials may be compromised or insufficiently protected. The DoS attack could interrupt synchronization services, impacting business continuity, data availability, and potentially causing operational delays. Organizations relying heavily on Qsync Central for file synchronization and collaboration may experience degraded productivity. While the vulnerability does not allow data exfiltration or modification, the availability impact could be significant for critical systems. Given the medium severity and the requirement for user-level privileges, the threat is moderate but should not be underestimated, especially in sectors where uptime and data synchronization are critical.

European organizations should promptly upgrade Qsync Central to version 4.5.0.7 or later to remediate the vulnerability. Beyond patching, organizations should enforce strong user authentication policies to reduce the risk of account compromise, including multi-factor authentication (MFA) where supported. Regularly audit user accounts and permissions to ensure that only authorized users have access. Network segmentation and firewall rules should limit access to Qsync Central services to trusted networks and users. Monitoring and alerting for unusual login activities or repeated service crashes can help detect exploitation attempts early. Additionally, organizations should implement robust backup and recovery procedures to mitigate the impact of potential service disruptions. Finally, maintaining an up-to-date inventory of QNAP products and versions deployed will facilitate timely vulnerability management.