Security Resilience

CVE-2023-21803

Memory Safety in Microsoft Windows 10 ≤ 10.0.10240.19747

Memory Safety
Published
14 February 2023
Modified
19 August 2026
Patch / advisory
View 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 0.018 78th percentile
Risk Priority 82 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-2023-21803 is a critical-severity Integer Overflow or Wraparound (CWE-190) vulnerability in Microsoft Windows 10. Its CVSS base score is 9.8 (Critical).

Operationally, exploitation aligns with the MITRE ATT&CK technique LSA Secrets (T1003.004); ranked in the top 22% 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.

CVE-2023-21803 is a remote code execution vulnerability in the Windows iSCSI Discovery Service. It received a CVSS v3.1 score of 9.8 and is associated with CWE-190 integer overflow or wraparound. The flaw affects the iSCSI component responsible for discovery operations in Windows environments.

Unauthenticated attackers can exploit the issue over the network without user interaction or credentials, achieving full control over confidentiality, integrity, and availability on affected systems. The EPSS score has remained steady at 0.1393 with no material increase after disclosure. Microsoft has published guidance at the listed MSRC URLs.

EU & UK References

Vulnerability Data

Windows iSCSI Discovery Service Remote Code Execution Vulnerability

CWE(s)
CWE-190NVD-CWE-noinfo

Related Threats

MITRE ATT&CK Enterprise Techniques

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.
attack.mitre.org →
T1003.005 Cached Domain Credentials Credential Access
Adversaries may attempt to access cached domain credentials used to allow authentication to occur in the event a domain controller is unavailable.
attack.mitre.org →
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…
attack.mitre.org →
T1003.008 /etc/passwd and /etc/shadow Credential Access
Adversaries may attempt to dump the contents of <code>/etc/passwd</code> and <code>/etc/shadow</code> to enable offline password cracking.
attack.mitre.org →
T1006 Direct Volume Access Stealth
Adversaries may directly access a volume to bypass file access controls and file system monitoring.
attack.mitre.org →
T1008 Fallback Channels Command And Control
Adversaries may use fallback or alternate communication channels if the primary channel is compromised or inaccessible in order to maintain reliable command and control and to avoid data transfer thresholds.
attack.mitre.org →
Derived from this CVE’s CWE(s) via the direct CWE→ATT&CK cross-walk.

CVEs Like This One

CVE-2023-21802Same product: Microsoft Windows 10
CVE-2023-36593Same product: Microsoft Windows 10
CVE-2023-36582Same product: Microsoft Windows 10
CVE-2023-36911Same product: Microsoft Windows 10
CVE-2023-36900Same product: Microsoft Windows 10
CVE-2023-36910Same product: Microsoft Windows 10
CVE-2023-35632Same product: Microsoft Windows 10 1607
CVE-2023-24908Same product: Microsoft Windows 10 1607
CVE-2023-23405Same product: Microsoft Windows 10 1607
CVE-2023-21823Same product: Microsoft Windows 10 1607

Affected Assets

microsoft
windows 10
≤ 10.0.10240.19747
microsoft
windows 10 1607
≤ 10.0.14393.5717
microsoft
windows 10 1809
≤ 10.0.17763.4010
microsoft
windows 10 20h2
≤ 10.0.19042.2604
microsoft
windows 10 21h2
≤ 10.0.19044.2604
microsoft
windows 10 22h2
≤ 10.0.19045.2604
microsoft
windows server 2008
all versions

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)
  • V5.2.6

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.

PR.PS-06 partial match
blocks

Secure SDLC practices directly require use of safe arithmetic, bounds checks, and testing that prevent integer 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.

A.5.14 Information transfer partial match
removes
A.5.15 Access control partial match
removes
A.5.16 Identity management partial match
removes
A.5.17 Authentication information partial match
removes
A.5.18 Access rights partial match
removes
A.8.10 Information deletion partial match
removes

References