CVE-2021-28442Network attack vector

Authenticated information disclosure via undisclosed TCP/IP flaw

Published Apr 13, 2021 · Updated Aug 3, 2024

Information disclosure in Microsoft Windows TCP/IP allows remote authenticated users to obtain unspecified data via network traffic. Microsoft has not published the affected TCP/IP routine, protocol field, or incorrect operation that exposes the data. Network access with low privileges is required; the reported impact is limited to confidentiality, with no data modification or service interruption.

CVSS severity6.5
Medium
EPSS probability6.49%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Information disclosure in Microsoft Windows TCP/IP allows remote authenticated users to obtain unspecified data via network traffic. Microsoft has not published the affected TCP/IP routine, protocol field, or incorrect operation that exposes the data. Network access with low privileges is required; the reported impact is limited to confidentiality, with no data modification or service interruption.

The record

CVE
CVE-2021-28442
Published
Apr 13, 2021
Updated
Aug 3, 2024
Vendor
Microsoft
Product
Windows Server 2019
Classifications
Unavailable
Attack vector
network
Privileges
authenticated

Timeline

How it unfolded

  1. Apr 13, 2021CVE publishedPublication date reported by the CVE source.
  2. Aug 3, 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=10.0.0 <publication

What conditions does exploitation require?

Attack vectornetwork
Required privilegesauthenticated

What is affected?

Microsoft · Windows Server 2019version=10.0.0 <publication
Microsoft · Windows 10 Version 1909version=10.0.0 <publication
Microsoft · Windows 10 Version 1803version=10.0.0 <publication
Microsoft · Windows Server, version 2004version=10.0.0 <publication
Microsoft · Windows 10 Version 20H2version=10.0.0 <publication
Microsoft · Windows Server 2019 (Server Core installation)version=10.0.0 <publication
Microsoft · Windows Server version 20H2version=10.0.0 <publication
Microsoft · Windows 10 Version 2004version=10.0.0 <publication
Microsoft · Windows 10 Version 1809version=10.0.0 <publication
Microsoft · Windows Server, version 1909 (Server Core installation)version=10.0.0 <publication

Published CVSS scores

4.0NVDAV:N/AC:L/Au:S/C:P/I:N/A:N
6.5NVDCVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:N/A:N
6.5MicrosoftCVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:N/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
Privilegesauthenticated
Known exploitationUnconfirmed
Public exploitUnconfirmed

Weakness, pattern, technique

No sourced classifications are available.

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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