Security Resilience

CVE-2023-21540

Microsoft Windows 10 1809

Published
10 January 2023
Modified
21 November 2024
CVSS Score v3.1 5.5
Click a component to see what it means
Raw vectorCVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:N/A:N
EPSS Score 0.0058 46th percentile
Risk Priority 50 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-2023-21540 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 at the 46th percentile by exploit likelihood (below the median); 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-2023-21540 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.

OWASP Top 10 for Web (2025)

EU & UK References

Vulnerability Data

Windows Cryptographic Information Disclosure Vulnerability

CWE(s)

Related Threats

CVEs Like This One

CVE-2023-21559Same product: Microsoft Windows 10 1809
CVE-2023-28274Same product: Microsoft Windows 10 1809
CVE-2023-21550Same product: Microsoft Windows 10 1809
CVE-2023-24937Same product: Microsoft Windows 10 1809
CVE-2023-32037Same product: Microsoft Windows 10 1809
CVE-2024-21304Same product: Microsoft Windows 10 1809
CVE-2024-30002Same product: Microsoft Windows 10 1809
CVE-2024-29998Same product: Microsoft Windows 10 1809
CVE-2023-24865Same product: Microsoft Windows 10 1809
CVE-2023-28302Same product: Microsoft Windows 10 1809

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.

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.

blocks

A.8.25 mandates security requirements, secure coding guidelines, checkpoints, testing (incl. code scans) and developer training in the SDLC, which reaches a slice of input validation defects but leaves the majority (incomplete enforcement, second-order inputs, parser differentials, post-validation canonicalization) unaddressed as in the SA-3 and A.8.28 anchors.

blocks

Mandating input controls that include integrity checks and input validation ensures that untrusted data is examined before use, blocking the root cause of many injection and malformed-data weaknesses.

blocks

Security-by-design principles explicitly call for data validation and sanitization at every layer, reducing the chance that malformed or malicious input will be processed without scrutiny.

prevents

Requiring language-specific secure coding standards, peer review, SAST and documented mitigation of common programming errors forces validation of all inputs before they are trusted.

finds

Testing against a defined set of requirements and using code review plus vulnerability scanning forces validation of inputs and handling of unanticipated conditions, reducing the chance that malformed data will be accepted.

Hardening callouts derived

DISA STIG baselines are authored against specific weaknesses. Where this CVE cites a broad weakness class, the mapping is not asserted at that abstraction (owner ruling, 2026-09-25: grade only at Base and below), so no rule is shown here rather than a rule shown against the wrong grain.

  • No fine-grained STIG row for CWE-20, a class-level weakness, and none of its children carries one either.

References