CVE-2021-38686Network attack vector

Remote compromise requiring user interaction

Published Nov 26, 2021 · Updated Sep 16, 2024

Improper authentication in QNAP QVR before 5.1.6 build 20211109 allows remote attackers to compromise VS Series NVR systems. QNAP has not published the affected authentication component or the incorrect operation it performs on untrusted input. Exploitation requires user interaction; the vendor describes a system security compromise but does not specify the resulting access or actions.

CVSS severity8.8
High
EPSS probability0.94%
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 QVR before 5.1.6 build 20211109 allows remote attackers to compromise VS Series NVR systems. QNAP has not published the affected authentication component or the incorrect operation it performs on untrusted input. Exploitation requires user interaction; the vendor describes a system security compromise but does not specify the resulting access or actions.

The record

CVE
CVE-2021-38686
Published
Nov 26, 2021
Updated
Sep 16, 2024
Vendor
Unknown vendor
Product
Unknown product
Classifications
CWE-287
Attack vector
network
Privileges
unauthenticated

Timeline

How it unfolded

  1. Nov 26, 2021CVE 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?

Affected buildAffected product and version details are unavailable.

What conditions does exploitation require?

Attack vectornetwork
Required privilegesunauthenticated

What is affected?

Affected products and versions are unavailable in this record.

Published CVSS scores

8.8NIST National Vulnerability DatabaseCVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H
6.8NIST National Vulnerability DatabaseAV:N/AC:M/Au:N/C:P/I:P/A:P
8.8QNAP Systems, Inc.CVSS:3.1/AV:N/AC:L/PR:N/UI:R/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 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.

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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