Security Resilience

CVE-2023-21689

Memory Safety in Microsoft Windows 10 1809 ≤ 10.0.17763.4010

Published
14 February 2023
Modified
19 August 2026
Patch / advisory
CVSS Score v3.1 9.8
Click a component to see what it means
Raw vectorCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
EPSS Score 0.27 98th percentile
Risk Priority 88 floored blend · peak EPSS

CVSS and EPSS are reproduced from their sources (NVD, FIRST EPSS). Risk Priority is our own derived reading, not an NVD score.

Summary

CVE-2023-21689 is a critical-severity Heap-based Buffer Overflow (CWE-122) vulnerability in Microsoft Windows 10 1809. Its CVSS base score is 9.8 (Critical).

Operationally, exploitation aligns with the MITRE ATT&CK technique Data Obfuscation (T1001); ranked in the top 2% of CVEs by exploit likelihood; it is not currently listed in the CISA KEV catalog.

Deeper analysis AI-assisted summary

Synthesised by an AI model from the NVD description and linked references — a reading aid, not an authoritative source.

Microsoft Protected Extensible Authentication Protocol (PEAP) contains a remote code execution vulnerability tracked as CVE-2023-21689. The flaw is present in the PEAP implementation used for network authentication in Microsoft Windows and related networking components. It received a CVSS 3.1 base score of 9.8, reflecting network-accessible attack vectors with low complexity and no required privileges or user interaction, and is associated with CWE-122 (heap-based buffer overflow).

An unauthenticated attacker able to reach a vulnerable PEAP endpoint can send specially crafted authentication messages that trigger the flaw, resulting in arbitrary code execution on the target system with full control over confidentiality, integrity, and availability. The attack requires only network adjacency to the affected service and does not depend on user interaction or credentials.

Microsoft’s advisory at https://msrc.microsoft.com/update-guide/vulnerability/CVE-2023-21689 provides the official patch and mitigation guidance. The current EPSS score of 0.2938 with a recorded peak of 0.3514 indicates moderate and sustained exploitation interest following disclosure.

EU & UK References

Vulnerability Data

Microsoft Protected Extensible Authentication Protocol (PEAP) Remote Code Execution Vulnerability

CWE(s)

Related Threats

MITRE ATT&CK Enterprise Techniques

T1001 Data Obfuscation Command And Control
Adversaries may obfuscate command and control traffic to make it more difficult to detect.
T1001.002 Steganography Command And Control
Adversaries may use steganographic techniques to hide command and control traffic to make detection efforts more difficult.
T1003.001 LSASS Memory Credential Access
Adversaries may attempt to access credential material stored in the process memory of the Local Security Authority Subsystem Service (LSASS).
T1003.004 LSA Secrets Credential Access
Adversaries with SYSTEM access to a host may attempt to access Local Security Authority (LSA) secrets, which can contain a variety of different credential materials, such as credentials for service accounts.
T1003.006 DCSync Credential Access
Adversaries may attempt to access credentials and other sensitive information by abusing a Windows Domain Controller's application programming interface (API)(Citation: Microsoft DRSR Dec 2017) (Citation: Microsoft GetNCCChanges) (Citati…
T1006 Direct Volume Access Stealth
Adversaries may directly access a volume to bypass file access controls and file system monitoring.
Derived from this CVE’s CWE(s) via the direct CWE→ATT&CK cross-walk.

CVEs Like This One

CVE-2023-24943Same product: Microsoft Windows 10 1507
CVE-2023-28275Same product: Microsoft Windows 10 1507
CVE-2023-28218Same product: Microsoft Windows 10 1507
CVE-2023-21690Same product: Microsoft Windows 10 1507
CVE-2023-24912Same product: Microsoft Windows 10 1507
CVE-2023-23415Same product: Microsoft Windows 10 1507
CVE-2023-28227Same product: Microsoft Windows 10 1507
CVE-2023-21692Same product: Microsoft Windows 10 1507
CVE-2023-21799Same product: Microsoft Windows 10 1507
CVE-2023-24926Same product: Microsoft Windows 10 1507

Affected Assets

microsoft
windows 10 1507
≤ 10.0.10240.19747 · ≤ 10.0.10240.19747
microsoft
windows 10 1607
≤ 10.0.14393.5717 · ≤ 10.0.14393.5717
microsoft
windows 10 1809
≤ 10.0.17763.4010 · ≤ 10.0.17763.4010 · ≤ 10.0.17763.4010
microsoft
windows 10 20h2
≤ 10.0.19042.2604 · ≤ 10.0.19042.2604 · ≤ 10.0.19042.2604
microsoft
windows 10 21h2
≤ 10.0.19044.2604 · ≤ 10.0.19044.2604 · ≤ 10.0.19044.2604
microsoft
windows 10 22h2
≤ 10.0.19045.2604 · ≤ 10.0.19045.2604 · ≤ 10.0.19045.2604
microsoft
windows 11 21h2
≤ 10.0.22000.1574 · ≤ 10.0.22000.1574
microsoft
windows 11 22h2
≤ 10.0.22621.1265 · ≤ 10.0.22621.1265
microsoft
windows server 2008
all versions, r2
microsoft
windows server 2012
all versions, r2
+3 more product configuration(s) — see NVD for full list

Mitigating Controls

Control response

Prevent
Stop it (NIST 800-53)

—

Detect
Catch it (NIST detect / respond)

—

Harden
Shrink the surface (DISA STIG)

—

Validate
Prove the fix (OWASP ASVS)
  • V1.4.1

Mitigating Controls (NIST CSF 2.0) AI

Derived directly from the weakness types (CWEs) cited in the NVD entry via our AI-authored CWE→CSF cross-walk (authority under review) — links open the control.

ID.RA-01 partial match
blocks

Vulnerability scanning and recording can discover heap-overflow flaws but does not prevent their introduction in code.

PR.PS-02 partial match
blocks

Timely patching removes known heap-overflow instances after they exist.

PR.PS-06 partial match
blocks

Secure-development practices directly require bounds checking and safe memory handling that prevent heap overflows.

Mitigating Controls (ISO/IEC 27001:2022 Annex A) AI

Derived directly from the weakness types (CWEs) cited in the NVD entry via our AI-authored CWE→ISO cross-walk (authority under review) — links open the control.

removes
removes
removes
removes
removes

References