CVE-2025-52855 in QTS
Summary
by MITRE • 10/03/2025
A NULL pointer dereference vulnerability has been reported to affect several QNAP operating system versions. If a remote attacker gains an administrator account, they can then exploit the vulnerability to launch a denial-of-service (DoS) attack.
We have already fixed the vulnerability in the following versions: QTS 5.2.6.3195 build 20250715 and later QuTS hero h5.2.6.3195 build 20250715 and later
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Analysis
by VulDB Data Team • 10/09/2025
This vulnerability represents a critical null pointer dereference flaw within QNAP's operating system implementations that can be exploited to execute denial-of-service attacks. The issue manifests when a remote attacker with administrative privileges manipulates specific system operations that lead to attempting to dereference a null pointer reference, causing the affected service or application to crash and terminate unexpectedly. The vulnerability specifically impacts QNAP's QTS and QuTS hero operating systems, where the flaw exists in the core system components that handle administrative operations and user session management.
The technical nature of this vulnerability aligns with CWE-476 which describes null pointer dereference conditions that occur when a program attempts to access memory through a pointer that has not been initialized or has been set to null. In QNAP's case, this occurs within administrative interfaces or system management modules where the application fails to properly validate input parameters or handle edge cases in user session processing. The flaw essentially creates a scenario where legitimate administrative operations can trigger unexpected program termination, effectively disabling the system's availability for authorized users while maintaining the attacker's elevated privileges.
From an operational perspective, this vulnerability presents a significant risk to organizations relying on QNAP storage solutions, particularly in enterprise environments where continuous system availability is critical. The attack vector requires an attacker to already possess administrative credentials, which reduces the initial attack surface but does not eliminate the threat entirely. Once an attacker has administrative access, they can systematically exploit this vulnerability to disrupt services, potentially causing extended downtime that affects data availability, backup operations, and overall network infrastructure reliability. The DoS condition can be particularly damaging in mission-critical environments where QNAP appliances serve as primary storage or backup solutions.
The remediation path for this vulnerability involves immediate deployment of the patched versions released by QNAP, specifically QTS 5.2.6.3195 build 20250715 and later, as well as QuTS hero h5.2.6.3195 build 20250715 and later. Organizations should implement comprehensive patch management procedures to ensure all affected devices receive the updates promptly. Security teams should also consider implementing monitoring solutions to detect potential exploitation attempts and establish incident response procedures that account for this specific vulnerability. The fix addresses the underlying null pointer dereference by implementing proper input validation and null pointer checks within the administrative processing modules, preventing the crash condition that previously occurred during specific user session operations.
This vulnerability demonstrates the importance of proper memory management and input validation in system administration interfaces, as highlighted by ATT&CK technique T1499 which covers network denial-of-service attacks. The issue also reflects broader security concerns around privilege escalation and lateral movement within storage infrastructure, where administrative access can be leveraged to cause system instability. Organizations should conduct thorough security assessments of their QNAP deployments and implement additional controls such as multi-factor authentication, network segmentation, and regular security audits to reduce the likelihood of administrative credential compromise and limit the impact of similar vulnerabilities in the future.