Vulnerability Database

328,409

Total vulnerabilities in the database

CVE-2021-44052

An improper link resolution before file access ('Link Following') vulnerability has been reported to affect QNAP device running QuTScloud, QuTS hero, and QTS. If exploited, this vulnerability allows remote attackers to traverse the file system to unintended locations and read or overwrite the contents of unexpected files. We have already fixed this vulnerability in the following versions of QuTScloud, QuTS hero, and QTS: QuTScloud c5.0.1.1998 and later QuTS hero h4.5.4.1971 build 20220310 and later QuTS hero h5.0.0.1986 build 20220324 and later QTS 4.3.4.1976 build 20220303 and later QTS 4.3.3.1945 build 20220303 and later QTS 4.2.6 build 20220304 and later QTS 4.3.6.1965 build 20220302 and later QTS 5.0.0.1986 build 20220324 and later QTS 4.5.4.1991 build 20220329 and later

  • Published: May 5, 2022
  • Updated: Nov 16, 2025
  • CVE: CVE-2021-44052
  • Severity: Medium
  • Exploit:

CVSS v3:

  • Severity: Medium
  • Score: 6.5
  • AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:N/A:N

CVSS v2:

  • Severity: Medium
  • Score: 5.5
  • AV:N/AC:L/Au:S/C:P/I:P/A:N

CWEs:

Software From Fixed in
qnap / quts_hero - h4.5.4.1771
qnap / qts 5.0.0.1716 5.0.0.1986
qnap / qts 4.4.0.0883 4.5.4.1991
qnap / qts 4.3.6.0895 4.3.6.1965
qnap / qts 4.3.4.0899 4.3.4.1976
qnap / qts 4.3.3.0174 4.3.3.1945
qnap / qts 4.2.6-build_20170517 4.2.6-build_20170517.x
qnap / qts 4.2.6-build_20190322 4.2.6-build_20190322.x
qnap / qts 4.2.6-build_20190730 4.2.6-build_20190730.x
qnap / qts 4.2.6-build_20190921 4.2.6-build_20190921.x
qnap / qts 4.2.6-build_20191107 4.2.6-build_20191107.x
qnap / qts 4.2.6-build_20200109 4.2.6-build_20200109.x
qnap / qts 4.2.6-build_20200421 4.2.6-build_20200421.x
qnap / qts 4.2.6-build_20200611 4.2.6-build_20200611.x
qnap / qts 4.2.6-build_20200821 4.2.6-build_20200821.x
qnap / qts 4.2.6-build_20210327 4.2.6-build_20210327.x
qnap / qts 4.2.6-build_20211215 4.2.6-build_20211215.x
qnap / quts_hero h5.0.0.1772 h5.0.0.1986
qnap / qutscloud - c5.0.1.1998

Frequently Asked Questions

A security vulnerability is a weakness in software, hardware, or configuration that can be exploited to compromise confidentiality, integrity, or availability. Many vulnerabilities are tracked as CVEs (Common Vulnerabilities and Exposures), which provide a standardized identifier so teams can coordinate patching, mitigation, and risk assessment across tools and vendors.

CVSS (Common Vulnerability Scoring System) estimates technical severity, but it doesn't automatically equal business risk. Prioritize using context like internet exposure, affected asset criticality, known exploitation (proof-of-concept or in-the-wild), and whether compensating controls exist. A "Medium" CVSS on an exposed, production system can be more urgent than a "Critical" on an isolated, non-production host.

A vulnerability is the underlying weakness. An exploit is the method or code used to take advantage of it. A zero-day is a vulnerability that is unknown to the vendor or has no publicly available fix when attackers begin using it. In practice, risk increases sharply when exploitation becomes reliable or widespread.

Recurring findings usually come from incomplete Asset Discovery, inconsistent patch management, inherited images, and configuration drift. In modern environments, you also need to watch the software supply chain: dependencies, containers, build pipelines, and third-party services can reintroduce the same weakness even after you patch a single host. Unknown or unmanaged assets (often called Shadow IT) are a common reason the same issues resurface.

Use a simple, repeatable triage model: focus first on externally exposed assets, high-value systems (identity, VPN, email, production), vulnerabilities with known exploits, and issues that enable remote code execution or privilege escalation. Then enforce patch SLAs and track progress using consistent metrics so remediation is steady, not reactive.

SynScan combines attack surface monitoring and continuous security auditing to keep your inventory current, flag high-impact vulnerabilities early, and help you turn raw findings into a practical remediation plan.