Cyber Resilience

CVE-2023-21540

Medium

Published: 10 January 2023

Published
10 January 2023
Modified
21 November 2024
KEV Added
Patch
CVSS Score v3.1 5.5 CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:N/A:N
EPSS Score 0.0582 90.7th percentile
Risk Priority 14 60% EPSS · 20% KEV · 20% CVSS

Summary

CVE-2023-21540 is a medium-severity Improper Input Validation (CWE-20) vulnerability in Microsoft Windows 10 1809. Its CVSS base score is 5.5 (Medium).

Operationally, ranked in the top 9.3% of CVEs by exploit likelihood; it is not currently listed in the CISA KEV catalog.

Deeper analysis

CVE-2023-21540 is a Windows Cryptographic Information Disclosure Vulnerability affecting the Windows cryptographic subsystem. It carries a CVSS 3.1 score of 5.5 with the vector AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:N/A:N and is associated with CWE-20. The flaw permits unauthorized exposure of sensitive cryptographic material on affected Windows systems.

An authenticated local attacker with low privileges can exploit the issue without user interaction to read high-value cryptographic information from the target system. The attack requires local access and does not impact integrity or availability.

Microsoft’s advisory at msrc.microsoft.com directs administrators to apply the security updates released for the vulnerability on 10 January 2023. The EPSS score has remained low and stable, with a current value of 0.0582 and a peak of 0.0592, indicating limited observed exploitation interest after disclosure.

EU & UK References

Vulnerability details

Windows Cryptographic Information Disclosure Vulnerability

CWE(s)

Related Threats

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

Affected Assets

microsoft
windows 10 1809
all versions
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 2019
all versions
microsoft
windows server 2022
all versions

Mitigating Controls

Likely Mitigating Controls AI

Per-CVE control mapping for this CVE has not run yet; the list below is derived from the weakness types (CWEs) cited in the NVD entry.

addresses: CWE-20

Security testing and developer training directly verify and enforce proper input validation, reducing exploitability of injection and malformed-data weaknesses.

addresses: CWE-20

Security testing and evaluation at multiple SDLC stages directly detects missing or flawed input validation, with the required remediation process ensuring fixes are applied.

addresses: CWE-20

Directly implements checks on information inputs to reject invalid data before processing.

addresses: CWE-20

Spam protection mechanisms perform filtering and detection on inbound/outbound messages, directly compensating for missing or weak input validation of unsolicited content.

References