CVE-2021-38679Network attack vector

Unauthenticated access via improper authentication

Published Feb 11, 2022 · Updated Sep 16, 2024

Improper authentication in QNAP Systems, Inc. Kazoo Server before 4.11.22 allows remote attackers to compromise system security via network requests. The advisory does not disclose which authentication locus accepts unauthenticated requests or what validation is bypassed. The issue requires network reachability to the Kazoo Server service; the published impact is compromise of system security without a more specific confidentiality, integrity, or availability consequence.

CVSS severity9.8
Critical
EPSS probability0.74%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Improper authentication in QNAP Systems, Inc. Kazoo Server before 4.11.22 allows remote attackers to compromise system security via network requests. The advisory does not disclose which authentication locus accepts unauthenticated requests or what validation is bypassed. The issue requires network reachability to the Kazoo Server service; the published impact is compromise of system security without a more specific confidentiality, integrity, or availability consequence.

The record

CVE
CVE-2021-38679
Published
Feb 11, 2022
Updated
Sep 16, 2024
Vendor
Linn Products Limited
Product
Kazoo Server
Classifications
CWE-287
Attack vector
network
Privileges
unauthenticated

Timeline

How it unfolded

  1. Feb 11, 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

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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 <4.11.22

What conditions does exploitation require?

Attack vectornetwork
Required privilegesunauthenticated

What is affected?

Linn Products Limited · Kazoo Serverversion=unspecified <4.11.22

Published CVSS scores

9.8NVDCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
7.5NVDAV:N/AC:L/Au:N/C:P/I:P/A:P
6.5QNAP Systems, Inc.CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:L/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 10, 2026Sep 16, 2026
Latest reporting daySep 16, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectornetwork
Privilegesunauthenticated
Known exploitationUnconfirmed
Public exploitUnconfirmed

Weakness, pattern, technique

CWE-287Improper Authentication

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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