Vulnerability in QNAP Qts
CVE-2025-66277
A link following vulnerability has been reported to affect several QNAP operating system versions. The remote attackers can then exploit the vulnerability to traverse the file system to unintended locations. We have already fixed the vulnerability in the following versions: QTS 5.2.8.3350 build 20251216 and later QuTS hero h5.3.2.3354 build 20251225 and later QuTS hero h5.2.8.3350 build 20251216 and later
Published · last modified .
CVSS v3 metric
CVSS v3 base score 9.8 (Critical). Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H.
EPSS exploit prediction
EPSS: 0.007 (49.5th percentile), scored .
Very low probability of exploitation in the next 30 days; routine patching cadence is appropriate. 49th percentile — 49.5% of CVEs in the catalogue have a lower EPSS than this one. How to read EPSS.
EPSS over last 30 days · oldest: 0.006 · newest: 0.007 · change: +0.000
Affected products
- QNAP Qts — versions 5.2.0.2737, 5.2.0.2744, 5.2.0.2782
- QNAP Quts Hero — versions h5.2.0.2737, h5.2.0.2782, h5.2.0.2789
- QNAP Systems Inc. Qts — versions 5.2.x
- QNAP Systems Inc. Quts Hero — versions h5.3.x, h5.2.x
Weakness classification (CWE)
References
- www.qnap.com/en/security-advisory/qsa-26-05 (Vendor Advisory)
Frequently asked questions
- What is CVE-2025-66277?
- CVE-2025-66277 is a critical-severity vulnerability in QNAP Qts, classified under Improper Link Resolution Before File Access. CVSS score: 9.8/10. Published 2026-02-11.
- How severe is CVE-2025-66277?
- Critical severity. CVSS v3 base score is 9.8 out of 10.