QTS, QuTS hero

published 2026-02-11 8 mo ago modified 2026-06-17 4 mo ago also EUVD-2025-207017

cvss: 9.8; version 3.1, NVD
cisa kev: Not listed; not in CISA's catalog
epss: 0.7%; EPSS 0.7% chance of exploitation in 30 days, percentile 53%
public exploits: 0; none known

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

Patch / fix

fixed in 2

QNAP Systems Inc. QTS 5.2.8.3350 build 20251216
QNAP Systems Inc. QuTS hero h5.2.8.3350 build 20251216, h5.3.2.3354 build 20251225

CISA SSVC

Exploitation: none
Automatable: yes
Technical impact: total
Assessed: 8 mo ago (2026-02-12)

Exploit prediction

0.70% chance of exploitation in the next 30 days, higher than 53% of all scored CVEs (FIRST EPSS, 2026-11-08).

CVSS scores

assigned by	version	score	vector
CNA	4.0	9.2	CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:N/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N
CNA	4.0	9.2	CVSS:4.0/AV:N/AC:L/AT:P/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
NVD	3.1	9.8	CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H

Affected products

QNAP Systems Inc. QTS
QNAP Systems Inc. QuTS hero

Classification

Weakness

CWE-59 Improper Link Resolution Before File Access

References

qnap.com /en/security-advisory/qsa-26-05
vendor-advisory

Sources

CVE List CVE-2025-66277
NVD CVE-2025-66277

Fencer Vulns keeps one entry per vulnerability: the CVE id wins, then GHSA, and records that alias each other are merged, except that two CVEs always keep separate entries. The same data is available as JSON.

Summary