CVE-2023-21691Network attack vector

Information disclosure via out-of-bounds PEAP read

Published Feb 14, 2023 · Updated Aug 19, 2026

Out-of-bounds read in Microsoft Windows PEAP allows remote attackers to disclose process memory through crafted PEAP packets. Microsoft identifies the weakness as CWE-125 but has not published the affected function or exact bounds-check failure. Reachability requires a Windows PEAP processing path, including an NPS network policy configured to permit PEAP on affected server deployments.

CVSS severity7.5
High
EPSS probability1.43%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Out-of-bounds read in Microsoft Windows PEAP allows remote attackers to disclose process memory through crafted PEAP packets. Microsoft identifies the weakness as CWE-125 but has not published the affected function or exact bounds-check failure. Reachability requires a Windows PEAP processing path, including an NPS network policy configured to permit PEAP on affected server deployments.

The record

CVE
CVE-2023-21691
Published
Feb 14, 2023
Updated
Aug 19, 2026
Vendor
Microsoft
Product
Windows 10 Version 1507
Classifications
CWE-125, T1005
Attack vector
network
Privileges
unauthenticated

Timeline

How it unfolded

  1. Feb 14, 2023CVE publishedPublication date reported by the CVE source.
  2. Aug 19, 2026Record updatedLatest update available in the CVE record.

Exploitability

Present is not the same as exploitable

Compare your product and version with the public record. A matching version still requires validation against your environment.

Is a vulnerable build present?

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

  1. Affected versionversion=10.0.10240.0 <10.0.10240.19747

What conditions does exploitation require?

Attack vectornetwork
Required privilegesunauthenticated

What is affected?

Microsoft · Windows 10 Version 1507version=10.0.10240.0 <10.0.10240.19747
Microsoft · Windows Server 2019version=10.0.17763.0 <10.0.17763.4010
Microsoft · Windows Server 2016 (Server Core installation)version=10.0.14393.0 <10.0.14393.5717
Microsoft · Windows 11 version 21H2version=10.0.0 <10.0.22621.1574
Microsoft · Windows Server 2012 (Server Core installation)version=6.2.9200.0 <6.2.9200.24116
Microsoft · Windows Server 2012version=6.2.9200.0 <6.2.9200.24116
Microsoft · Windows 10 Version 21H2version=10.0.19043.0 <10.0.19044.2604
Microsoft · Windows Server 2016version=10.0.14393.0 <10.0.14393.5717
Microsoft · Windows Server 2008 R2 Service Pack 1version=6.1.7601.0 <6.1.7601.26366
Microsoft · Windows 10 Version 20H2version=10.0.0 <10.0.19042.2604
Microsoft · Windows Server 2008 R2 Service Pack 1 (Server Core installation)version=6.1.7601.0 <6.1.7601.26366
Microsoft · Windows 10 Version 22H2version=10.0.19045.0 <10.0.19045.2604
Microsoft · Windows Server 2012 R2 (Server Core installation)version=6.3.9600.0 <6.3.9600.20821
Microsoft · Windows Server 2019 (Server Core installation)version=10.0.17763.0 <10.0.17763.4010
Microsoft · Windows 11, version 22H2version=10.0.22621.0 <10.0.22621.1265
Microsoft · Windows 10 Version 1607version=10.0.14393.0 <10.0.14393.5717
Microsoft · Windows Server 2008 Service Pack 2version=6.0.6003.0 <6.0.6003.21915
Microsoft · Windows Server 2022version=10.0.20348.0 <10.0.20348.1547
Microsoft · Windows 10 Version 1809version=10.0.0 <10.0.17763.4010; version=10.0.17763.0 <10.0.17763.4010
Microsoft · Windows Server 2012 R2version=6.3.9600.0 <6.3.9600.20821
Microsoft · Windows Server 2008 Service Pack 2 (Server Core installation)version=6.0.6003.0 <6.0.6003.21915

Published CVSS scores

7.5Microsoft CorporationCVSS:3.1/AV:N/AC:L/PR:N/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 9, 2026Sep 15, 2026
Latest reporting daySep 15, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectornetwork
Privilegesunauthenticated
Known exploitationUnconfirmed
Public exploitUnconfirmed

Weakness, pattern, technique

CWE-125Out-of-bounds Read
T1005Data from Local System

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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