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.

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 vuln…

EPSS: 0.006 (45.8th percentile) — read the EPSS interpretation.

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.

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)

CWE-59 — Improper Link Resolution Before File Access

References

security@qnapsecurity.com.tw (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.