CVE-2025-66277 | QTS, QuTS hero

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: 2026-02-11 Last update: 2026-06-17 Assigner: [email protected] Source: [email protected]
NVD Status：Analyzed，CVE State: published
View at NVD, CVE.org, EUVD

CVE-2025-66277 is rated Moderate Risk (53.2/100): CVSS Critical severity, with low exploitation likelihood (EPSS 0.63%). Review affected assets and schedule remediation.

Risk is dynamic; we continuously reassess and refresh what is shown on this page as upstream context changes.

Exploit prediction scoring system (EPSS) score for CVE-2025-66277

EPSS lead: Daily EPSS estimates relative likelihood of exploitation; percentile ranks this CVE among scored vulnerabilities (higher = more severe relative rank).

# Date Old EPSS score New EPSS score Delta (New - Old)
1 2026-06-15 0.08% 0.63% +0.56%
2 2026-02-12 — 0.08% —

Full EPSS history (2 records total)

Common vulnerability scoring system (CVSS) metrics for CVE-2025-66277

CVSS metrics for this CVE.

Base score Version Severity Vector Exploitability Impact Score source
9.2 4.0 CRITICAL
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 Click to expand
Attack vector (AV:N)
Could be attacked over the internet or any normal routed network.
Attack complexity (AC:L)
Exploitation conditions are straightforward and stable.
Attack requirements (AT:P)
Additional preconditions must be present for exploitation.
Privileges required (PR:N)
No privileges are required.
User interaction (UI:N)
No user interaction is required.
Vulnerable system confidentiality impact (VC:H)
High confidentiality impact on the vulnerable system.
Vulnerable system integrity impact (VI:H)
High integrity impact on the vulnerable system.
Vulnerable system availability impact (VA:H)
High availability impact on the vulnerable system.
Subsequent system confidentiality impact (SC:N)
No confidentiality impact on subsequent systems.
Subsequent system integrity impact (SI:N)
No integrity impact on subsequent systems.
Subsequent system availability impact (SA:N)
No availability impact on subsequent systems.
Exploit maturity (threat) (E:X)
Not defined: no reliable threat intelligence; scoring assumes the worst case (equivalent to Attacked).
Confidentiality requirement (CR:X)
Not defined: insufficient information; scoring treats this like High (worst case).
Integrity requirement (IR:X)
Not defined: insufficient information; scoring treats this like High (worst case).
Availability requirement (AR:X)
Not defined: insufficient information; scoring treats this like High (worst case).
Modified attack vector (MAV:X)
Not defined: scoring uses the Base Attack Vector (AV).
Modified attack complexity (MAC:X)
Not defined: scoring uses the Base Attack Complexity (AC).
Modified attack requirements (MAT:X)
Not defined: scoring uses the Base Attack Requirements (AT).
Modified privileges required (MPR:X)
Not defined: scoring uses the Base Privileges Required (PR).
Modified user interaction (MUI:X)
Not defined: scoring uses the Base User Interaction (UI).
Modified vulnerable system confidentiality impact (MVC:X)
Not defined: scoring uses the Base VC metric.
Modified vulnerable system integrity impact (MVI:X)
Not defined: scoring uses the Base VI metric.
Modified vulnerable system availability impact (MVA:X)
Not defined: scoring uses the Base VA metric.
Modified subsequent system confidentiality impact (MSC:X)
Not defined: scoring uses the Base SC metric.
Modified subsequent system integrity impact (MSI:X)
Not defined: scoring uses the Base SI metric.
Modified subsequent system availability impact (MSA:X)
Not defined: scoring uses the Base SA metric.
Safety (supplemental) (S:X)
Not evaluated.
Automatable (supplemental) (AU:X)
Not evaluated.
Recovery (supplemental) (R:X)
Not evaluated.
Value density (supplemental) (V:X)
Not evaluated.
Vulnerability response effort (supplemental) (RE:X)
Not evaluated.
Provider urgency (supplemental) (U:X)
Not evaluated.
 — — [email protected]
9.8 3.1 CRITICAL
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H Click to expand
Attack vector (AV:N)
Could be attacked over the internet or any normal routed network—not just someone sitting at the machine.
Attack complexity (AC:L)
Once they can reach the bug, pulling it off is straightforward—no weird race conditions or rare setup.
Privileges required (PR:N)
No account or special rights needed—anonymous or random user is enough.
User interaction (UI:N)
Nobody has to click “OK” or open a trap file; it can work without a victim helping.
Scope (S:U)
Damage stays in the same “trust bubble” as the broken component—no big spill into unrelated systems.
Confidentiality (C:H)
Serious risk that confidential data gets exposed in a big way.
Integrity (I:H)
They could widely tamper with or forge data—trust in the data is badly hurt.
Availability (A:H)
Could take the service down hard or make it unusable for people who depend on it.
 3.9 5.9 [email protected]

Weakness enumeration for CVE-2025-66277

Affected software / configurations for CVE-2025-66277

Vendor Product Version Raw CPE
qnap qts 5.2.0.2737 cpe:2.3:o:qnap:qts:5.2.0.2737:build_20240417:*:*:*:*:*:*
qnap qts 5.2.0.2744 cpe:2.3:o:qnap:qts:5.2.0.2744:build_20240424:*:*:*:*:*:*
qnap qts 5.2.0.2782 cpe:2.3:o:qnap:qts:5.2.0.2782:build_20240601:*:*:*:*:*:*
qnap qts 5.2.0.2802 cpe:2.3:o:qnap:qts:5.2.0.2802:build_20240620:*:*:*:*:*:*
qnap qts 5.2.0.2823 cpe:2.3:o:qnap:qts:5.2.0.2823:build_20240711:*:*:*:*:*:*
qnap qts 5.2.0.2851 cpe:2.3:o:qnap:qts:5.2.0.2851:build_20240808:*:*:*:*:*:*
qnap qts 5.2.0.2860 cpe:2.3:o:qnap:qts:5.2.0.2860:build_20240817:*:*:*:*:*:*
qnap qts 5.2.1.2930 cpe:2.3:o:qnap:qts:5.2.1.2930:build_20241025:*:*:*:*:*:*
qnap qts 5.2.2.2950 cpe:2.3:o:qnap:qts:5.2.2.2950:build_20241114:*:*:*:*:*:*
qnap qts 5.2.3.3006 cpe:2.3:o:qnap:qts:5.2.3.3006:build_20250108:*:*:*:*:*:*
qnap qts 5.2.4.3070 cpe:2.3:o:qnap:qts:5.2.4.3070:build_20250312:*:*:*:*:*:*
qnap qts 5.2.4.3079 cpe:2.3:o:qnap:qts:5.2.4.3079:build_20250321:*:*:*:*:*:*
qnap qts 5.2.4.3092 cpe:2.3:o:qnap:qts:5.2.4.3092:build_20250403:*:*:*:*:*:*
qnap qts 5.2.5.3145 cpe:2.3:o:qnap:qts:5.2.5.3145:build_20250526:*:*:*:*:*:*
qnap qts 5.2.6.3195 cpe:2.3:o:qnap:qts:5.2.6.3195:build_20250715:*:*:*:*:*:*
qnap qts 5.2.6.3229 cpe:2.3:o:qnap:qts:5.2.6.3229:build_20250818:*:*:*:*:*:*
qnap qts 5.2.7.3256 cpe:2.3:o:qnap:qts:5.2.7.3256:build_20250913:*:*:*:*:*:*
qnap qts 5.2.7.3297 cpe:2.3:o:qnap:qts:5.2.7.3297:build_20251024:*:*:*:*:*:*
qnap qts 5.2.8.3332 cpe:2.3:o:qnap:qts:5.2.8.3332:build_20251128:*:*:*:*:*:*
qnap quts_hero h5.2.0.2737 cpe:2.3:o:qnap:quts_hero:h5.2.0.2737:build_20240417:*:*:*:*:*:*
qnap quts_hero h5.2.0.2782 cpe:2.3:o:qnap:quts_hero:h5.2.0.2782:build_20240601:*:*:*:*:*:*
qnap quts_hero h5.2.0.2789 cpe:2.3:o:qnap:quts_hero:h5.2.0.2789:build_20240607:*:*:*:*:*:*
qnap quts_hero h5.2.0.2802 cpe:2.3:o:qnap:quts_hero:h5.2.0.2802:build_20240620:*:*:*:*:*:*
qnap quts_hero h5.2.0.2823 cpe:2.3:o:qnap:quts_hero:h5.2.0.2823:build_20240711:*:*:*:*:*:*
qnap quts_hero h5.2.0.2851 cpe:2.3:o:qnap:quts_hero:h5.2.0.2851:build_20240808:*:*:*:*:*:*
qnap quts_hero h5.2.0.2860 cpe:2.3:o:qnap:quts_hero:h5.2.0.2860:build_20240817:*:*:*:*:*:*
qnap quts_hero h5.2.1.2929 cpe:2.3:o:qnap:quts_hero:h5.2.1.2929:build_20241025:*:*:*:*:*:*
qnap quts_hero h5.2.1.2940 cpe:2.3:o:qnap:quts_hero:h5.2.1.2940:build_20241105:*:*:*:*:*:*
qnap quts_hero h5.2.2.2952 cpe:2.3:o:qnap:quts_hero:h5.2.2.2952:build_20241116:*:*:*:*:*:*
qnap quts_hero h5.2.3.3006 cpe:2.3:o:qnap:quts_hero:h5.2.3.3006:build_20250108:*:*:*:*:*:*
qnap quts_hero h5.2.4.3070 cpe:2.3:o:qnap:quts_hero:h5.2.4.3070:build_20250312:*:*:*:*:*:*
qnap quts_hero h5.2.4.3079 cpe:2.3:o:qnap:quts_hero:h5.2.4.3079:build_20250321:*:*:*:*:*:*
qnap quts_hero h5.2.5.3138 cpe:2.3:o:qnap:quts_hero:h5.2.5.3138:build_20250519:*:*:*:*:*:*
qnap quts_hero h5.2.6.3195 cpe:2.3:o:qnap:quts_hero:h5.2.6.3195:build_20250715:*:*:*:*:*:*
qnap quts_hero h5.2.7.3256 cpe:2.3:o:qnap:quts_hero:h5.2.7.3256:build_20250913:*:*:*:*:*:*
qnap quts_hero h5.2.7.3297 cpe:2.3:o:qnap:quts_hero:h5.2.7.3297:build_20251024:*:*:*:*:*:*
qnap quts_hero h5.2.8.3321 cpe:2.3:o:qnap:quts_hero:h5.2.8.3321:build_20251117:*:*:*:*:*:*

References for CVE-2025-66277

cvelogic Threat Intelligence