CVE-2021-28814Network attack vector

Authenticated privilege escalation

Published Jun 11, 2021 · Updated Sep 17, 2024

Improper access control in QNAP Helpdesk before 3.0.4 allows remote authenticated users to compromise a QNAP NAS through excess privileges. QNAP has not published the affected endpoint or the incorrect authorization operation performed by Helpdesk. Low-privileged authentication is required; successful exploitation grants access beyond assigned privileges and can expose, alter, or interrupt NAS data and services.

CVSS severity8.8
High
EPSS probability1.23%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Improper access control in QNAP Helpdesk before 3.0.4 allows remote authenticated users to compromise a QNAP NAS through excess privileges. QNAP has not published the affected endpoint or the incorrect authorization operation performed by Helpdesk. Low-privileged authentication is required; successful exploitation grants access beyond assigned privileges and can expose, alter, or interrupt NAS data and services.

The record

CVE
CVE-2021-28814
Published
Jun 11, 2021
Updated
Sep 17, 2024
Vendor
Linn Products Limited
Product
Helpdesk
Classifications
CWE-269, T1068
Attack vector
network
Privileges
authenticated

Timeline

How it unfolded

  1. Jun 11, 2021CVE publishedPublication date reported by the CVE source.
  2. Sep 17, 2024Record updatedLatest update available in the CVE record.

Exploitability

Present is not the same as exploitable

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Is a vulnerable build present?

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

  1. Affected versionversion=unspecified <3.0.4

What conditions does exploitation require?

Attack vectornetwork
Required privilegesauthenticated

What is affected?

Linn Products Limited · Helpdeskversion=unspecified <3.0.4

Published CVSS scores

6.5NIST NVDAV:N/AC:L/Au:S/C:P/I:P/A:P
8.8QNAP Systems, Inc.CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H

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-269Improper Privilege Management
T1068Exploitation for Privilege Escalation

Public exploit references

No public exploit references are available in this record.

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Technologies

Your stack

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Your stack

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