Cyber Resilience

CVE-2023-21539

High

Published: 10 January 2023

Published
10 January 2023
Modified
21 November 2024
KEV Added
Patch
CVSS Score v3.1 7.5 CVSS:3.1/AV:N/AC:H/PR:L/UI:N/S:U/C:H/I:H/A:H
EPSS Score 0.0305 87.0th percentile
Risk Priority 17 60% EPSS · 20% KEV · 20% CVSS

Summary

CVE-2023-21539 is a high-severity Out-of-bounds Read (CWE-125) vulnerability in Microsoft Windows 10 20H2. Its CVSS base score is 7.5 (High).

Operationally, ranked in the top 13.0% of CVEs by exploit likelihood; it is not currently listed in the CISA KEV catalog.

Deeper analysis

CVE-2023-21539 is a remote code execution vulnerability affecting the Windows Authentication component. It carries a CVSS 3.1 base score of 7.5 and is associated with CWE-125. The flaw permits an attacker to execute arbitrary code on an affected system when specific conditions are met during authentication processing.

An authenticated user with low privileges can exploit the issue over a network connection, though successful exploitation requires high attack complexity and no user interaction. Successful attacks can result in full compromise of confidentiality, integrity, and availability on the target system.

Microsoft security advisories for CVE-2023-21539, available at the referenced MSRC update guide, detail the affected Windows versions and the corresponding security updates that address the vulnerability.

The EPSS score for this CVE rose from lower values to a peak of 0.0976 on 2025-01-22 before receding to the current 0.0305, indicating a period of increased exploitation interest after disclosure.

EU & UK References

Vulnerability details

Windows Authentication Remote Code Execution Vulnerability

CWE(s)

Related Threats

No named actor attribution yet. ATT&CK technique mapping in progress for this CVE.

Affected Assets

microsoft
windows 10 20h2
all versions
microsoft
windows 10 21h2
all versions
microsoft
windows 10 22h2
all versions
microsoft
windows 11 21h2
all versions
microsoft
windows 11 22h2
all versions
microsoft
windows server 2022
all versions

Mitigating Controls

No mitigating controls mapped yet. The per-CVE control annotator has not reached this CVE.

References