CVE-2021-28324Network attack vector

Unauthenticated data disclosure via undisclosed SMB flaw

Published Apr 13, 2021 · Updated Aug 3, 2024

Information disclosure in Microsoft Windows SMB allows remote attackers to access confidential data over the network without authentication. Microsoft has not published the affected SMB component, the triggering request, or the operation that exposes the data. The disclosed impact is limited to confidentiality; no user interaction or prior privileges are required, and integrity and availability are unaffected.

CVSS severity7.5
High
EPSS probability6.22%
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 SMB allows remote attackers to access confidential data over the network without authentication. Microsoft has not published the affected SMB component, the triggering request, or the operation that exposes the data. The disclosed impact is limited to confidentiality; no user interaction or prior privileges are required, and integrity and availability are unaffected.

The record

CVE
CVE-2021-28324
Published
Apr 13, 2021
Updated
Aug 3, 2024
Vendor
Microsoft
Product
Windows Server, version 2004
Classifications
T1210
Attack vector
network
Privileges
unauthenticated

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 privilegesunauthenticated

What is affected?

Microsoft · Windows Server, version 2004version=10.0.0 <publication
Microsoft · Windows 10 Version 20H2version=10.0.0 <publication
Microsoft · Windows Server version 20H2version=10.0.0 <publication
Microsoft · Windows 10 Version 2004version=10.0.0 <publication

Published CVSS scores

7.5Microsoft CorporationCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:N
5.0NIST NVDAV:N/AC:L/Au:N/C:P/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
Privilegesunauthenticated
Known exploitationUnconfirmed
Public exploitUnconfirmed

Weakness, pattern, technique

T1210Exploitation of Remote Services

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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