Which versions of Qvr are affected by CVE-2025-52856?

Organizations using the following face critical risk from CVE-2025-52856, a improper authentication vulnerability rated CVSS 9.3.

How to fix or mitigate CVE-2025-52856?

Within 24 hours: Identify all affected systems running the following and apply vendor patches immediately. Audit authentication configurations and rotate any potentially compromised credentials.

Qvr CVE-2025-52856

Q: What is the CVSS score of CVE-2025-52856?

CVE-2025-52856 has a CVSS 4.0 base score of 9.3 (Critical). CVSS vector: CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X. EPSS exploitation probability: 0.4%.

CRITICAL

Improper Authentication (CWE-287)

2025-08-29 security@qnapsecurity.com.tw

Authentication Bypass Qvr

9.3

CVSS 4.0 · NVD

Severity by source

NVD PRIMARY

9.3 CRITICAL

CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X

Primary rating from NVD · only source for this CVE.

CVSS VectorNVD

CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X

Attack Vector

Network

Attack Complexity

Low

Privileges Required

None

User Interaction

None

Scope

Lifecycle Timeline

Analysis Generated

Mar 28, 2026 - 19:09 vuln.today

CVE Published

Aug 29, 2025 - 18:15 nvd

CRITICAL 9.3

DescriptionCVE.org

An improper authentication vulnerability has been reported to affect VioStor. If a remote attacker, they can then exploit the vulnerability to compromise the security of the system.

We have already fixed the vulnerability in the following version: VioStor 5.1.6 build 20250621 and later

AnalysisAI

An improper authentication vulnerability has been reported to affect VioStor. Rated critical severity (CVSS 9.3), this vulnerability is remotely exploitable, no authentication required, low attack complexity. No vendor patch available.

Technical ContextAI

This vulnerability is classified as Improper Authentication (CWE-287), which allows attackers to bypass authentication mechanisms to gain unauthorized access. An improper authentication vulnerability has been reported to affect VioStor. If a remote attacker, they can then exploit the vulnerability to compromise the security of the system. We have already fixed the vulnerability in the following version: VioStor 5.1.6 build 20250621 and later Affected products include: Qnap Qvr.

RemediationAI

No vendor patch is available at time of analysis. Monitor vendor advisories for updates. Implement multi-factor authentication, enforce strong password policies, use proven authentication frameworks.