Qts
CVE-2025-66277
CRITICAL
Vulnerability Assessment
| Weakness |
CWE
OWASP Top 10:2025
A01:2025 - Broken Access Control
ASVS 5.0
V5 - File Handling Symlink resolution safety
|
| Impact | CVSS 9.8. QNAP NAS devices store business data, backups, and personal files. |
| Exploit ScenarioDerived | Remote attacker exploits symlink following to read/write files on the NAS beyond intended access scope. |
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Alert meAnalysisAIv1 – Mar 12, 2026
Symlink following vulnerability in multiple QNAP NAS operating system versions allows remote attackers to exploit link resolution for unauthorized access.
Earlier versions of this analysis (1)
Symlink following in QNAP NAS operating system.
RemediationAI
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Affects your stack
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Technical ContextAI · show details
CWE-59 link following vulnerability. QNAP NAS follows symlinks allowing access to files outside intended scope.
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- Exploit and PoC references, threat intelligence from 22 sources
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Severity by source
AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
Primary rating from NVD · only source for this CVE.
CVSS VectorNVD
DescriptionCVE.org
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
Executive ViewAI
A critical vulnerability (CVE-2025-66277, CVSS 9.8) in QNAP operating systems allows remote attackers to traverse file systems and access unauthorized data. This poses an immediate risk to any organization using affected QNAP devices, potentially exposing sensitive business data, configurations, and system files without requiring authentication.
Until vendor patch is available: (1) Implement network-level access controls restricting QNAP device connectivity to authorized users/systems only; (2) Deploy WAF or reverse proxy rules to block suspicious path traversal patterns (../, encoded variants); (3) Disable unnecessary QNAP services and management interfaces; (4) Segment QNAP devices on isolated VLANs; (5) Enable comprehensive audit logging and implement SIEM alerting for file access anomalies; (6) Consider temporary service degradation by taking non-critical QNAP devices offline until patch becomes available.
Threat Intelligence Overview
How this decision was reached
The engine reads each signal below and applies a fixed list of rules from top to bottom. The first rule that matches sets the recommended action – like a statement, every line is shown.
What every action level means
SSVC AssessmentENISA
Priority Score
Affected Products (CPE)CVE.org
GNU Bash through 4.3 processes trailing strings after function definitions in the values of environment variables, which
GNU Bash through 4.3 bash43-025 processes trailing strings after certain malformed function definitions in the values of
QNAP QTS before 4.2.4 Build 20170313 allows attackers to execute arbitrary commands via unspecified vectors. Rated criti
QNAP QTS before 4.2.4 Build 20170313 allows attackers to gain administrator privileges and obtain sensitive information
QNAP has patched a remote code execution vulnerability affecting the QTS Media Library in all versions prior to QTS 4.2.
QNAP QTS before 4.2.4 Build 20170313 allows attackers to gain administrator privileges and execute arbitrary commands vi
QNAP QTS before 4.2.4 Build 20170313 allows local users to obtain sensitive Domain Administrator password information by
This command injection vulnerability in QTS allows attackers to run arbitrary commands in the compromised application. R
This improper input validation vulnerability allows remote attackers to inject arbitrary code to the system. Rated criti
A prototype pollution vulnerability has been reported to affect several QNAP operating system versions. Rated high sever
A buffer overflow vulnerability in external device function in QNAP QTS version 4.2.6 build 20171026, 4.3.3.0378 build 2
A buffer overflow vulnerability in password function in QNAP QTS version 4.2.6 build 20171026, 4.3.3.0378 build 20171117
NVD
CVE.org
EPSS
GitHub PoC
Exploit-DB