CVE-2021-44052Network attack vector

Arbitrary file read and overwrite via link following

Published May 5, 2022 · Updated Sep 16, 2024

Improper link resolution in QNAP QTS, QuTS hero, and QuTScloud allows remote authenticated users to read or overwrite arbitrary files. File-access path resolution follows attacker-controlled links without restricting the resolved target to the intended location. Low-privileged network access is required; successful exploitation exposes file contents or overwrites files outside the intended path.

CVSS severity6.5
Medium
EPSS probability1.57%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Improper link resolution in QNAP QTS, QuTS hero, and QuTScloud allows remote authenticated users to read or overwrite arbitrary files. File-access path resolution follows attacker-controlled links without restricting the resolved target to the intended location. Low-privileged network access is required; successful exploitation exposes file contents or overwrites files outside the intended path.

The record

CVE
CVE-2021-44052
Published
May 5, 2022
Updated
Sep 16, 2024
Vendor
Linn Products Limited
Product
QuTS hero
Classifications
CWE-59, T1565.001, T1005
Attack vector
network
Privileges
authenticated

Timeline

How it unfolded

  1. May 5, 2022CVE publishedPublication date reported by the CVE source.
  2. Sep 16, 2024Record updatedLatest update available in the CVE record.

Exploitability

Present is not the same as exploitable

Compare your product and version with the public record. A matching version still requires validation against your environment.

Is a vulnerable build present?

Compare these published version ranges with your installed build and any vendor patches.

  1. Affected versionversion=unspecified <h4.5.4.1971 build 20220310
  2. Affected versionversion=unspecified <h5.0.0.1986 build 20220324

What conditions does exploitation require?

Attack vectornetwork
Required privilegesauthenticated

What is affected?

Linn Products Limited · QuTS heroversion=unspecified <h4.5.4.1971 build 20220310; version=unspecified <h5.0.0.1986 build 20220324
Linn Products Limited · QuTScloudversion=unspecified <c5.0.1.1998
Linn Products Limited · QTSversion=unspecified <4.2.6 build 20220304; version=unspecified <4.3.3.1945 build 20220303; version=unspecified <4.3.4.1976 build 20220303; version=unspecified <4.3.6.1965 build 20220302; version=unspecified <4.5.4.1991 build 20220329; version=unspecified <5.0.0.1986 build 20220324

Published CVSS scores

6.5QNAP Systems, Inc.CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:N/A:N
5.5NIST NVDAV:N/AC:L/Au:S/C:P/I:P/A:N
8.1NIST NVDCVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:N

CVSS describes severity. EPSS estimates exploitation probability.

Attacks

What attackers are doing with it

Daily unique IPs observed by Shadowserver honeypots for known exploited vulnerabilities (KEVs). Missing observations do not establish an absence of attacks.

Daily unique IPsNo honeypot observations are available for this CVE in the selected window.

No observations available

Sep 9, 2026Sep 15, 2026
Latest reporting daySep 15, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectornetwork
Privilegesauthenticated
Known exploitationUnconfirmed
Public exploitUnconfirmed

Weakness, pattern, technique

CWE-59Improper Link Resolution Before File Access ('Link Following')
T1565.001Stored Data Manipulation
T1005Data from Local System

Public exploit references

No public exploit references are available in this record.

Labels summarize the accepted research assessment. They do not indicate a test against your environment.

Technologies

Your stack

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Your stack

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