CVE-2025-52856 VioStor

What is CVE-2025-52856?

CVE-2025-52856 is a critical authentication bypass vulnerability in QNAP Systems Inc. VioStor, published on 29 Aug 2025. An attacker can exploit it over the internet without logging in, with no action from the victim.

Official description

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

Weakness: CWE-287

Which versions are affected by CVE-2025-52856?

It affects 1 product.

Products include Qnap Qvr.

How do I fix CVE-2025-52856?

No fix has been published for CVE-2025-52856 yet. Limit exposure of the affected software until one is available.

Upgrade, and rotate credentials and sessions that may have been exposed. More about Authentication bypass.

Is CVE-2025-52856 being exploited?

There is no known exploitation of CVE-2025-52856 in the wild and no public exploit code.

Other vulnerabilities in QNAP Systems Inc. VioStor

• CVE-2022-27588 Vulnerability in QVR Critical 9.8
• CVE-2021-38685 Command Injection Vulnerability in VioStor Critical 9.8
• CVE-2021-34348 Command Injection Vulnerability in QVR Critical 9.8
• CVE-2021-34351 Command Injection Vulnerability in QVR Critical 9.8
• CVE-2021-38686 Improper Authentication Vulnerability in VioStor High 8.8

Sources

• CVE record
• NVD
• OSV
• GitHub advisory
• How this page is made

Also known as GHSA-fjh8-m5r5-9wrm.