Is CVE-2023-21687 in the CISA KEV catalog?

No. CVE-2023-21687 is not currently on the CISA Known Exploited Vulnerabilities list.

What is the CVSS severity of CVE-2023-21687?

CVE-2023-21687 has a CVSS v3 base score of 5.5 (MEDIUM).

What is the EPSS score for CVE-2023-21687?

CVE-2023-21687 has an EPSS score of 0.46% (37th percentile), estimating the probability of exploitation in the next 30 days.

How do I fix CVE-2023-21687?

Install KB5022845 for Windows 11 Version 22H2. Fixes are available for 4 affected products.

CVE & CISA-KEV Catalog

CVE-2023-21687

MEDIUM

5.5

CVSS v3

NVD

Description

HTTP.sys Information Disclosure Vulnerability

CWE-125Out-of-bounds Read CWE-668

How to fix

Remediation Available

Windows 11 Version 22H2Windows

Install:KB5022845Microsoft

Windows 11 version 21H2Windows

Install:KB5022836Microsoft

Windows Server 2022Windows

Install:KB5022842Microsoft

Install:KB5022921

Windows Server 2022 (Server Core installation)Windows

Install:KB5022842Microsoft

Install:KB5022921

Remediation is compiled from vendor and distribution security advisories. Always confirm against the linked source for your exact version and platform.

CVSS v3 Vector

Exploitability

Attack VectorLocal

Attack ComplexityLow

Privileges RequiredLow

User InteractionNone

ScopeUnchanged

Impact

ConfidentialityHigh

IntegrityNone

AvailabilityNone

CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:N/A:N

Exploit Intelligence

0.46%probability of exploitation in 30 days

37thpercentile

Low risk: more likely to be exploited than 37% of all known CVEs.

References

Patch1

msrc.microsoft.com

Related Vulnerabilities

Other CWE-125 (Out-of-bounds Read) vulnerabilities, ordered by exploit likelihood. View all

CVE	Severity	CVSS	EPSS	Exploited	Fix
CVE-2014-0160	High	7.5	100%	KEV	Fix
CVE-2025-5777	High	7.5	100%	KEV + Ransom	Fix
CVE-2021-4034	High	7.8	95%	KEV	Fix
CVE-2023-21769	High	7.5	92%	-	Fix
CVE-2023-49285	High	8.6	89%	-	Fix
CVE-2020-8794	Critical	9.8	89%	-	Fix

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This product uses NVD data but is not endorsed or certified by the NVD. EPSS scores courtesy of FIRST.org (https://www.first.org/epss). Source: CISA KEV Catalog. Data as of 2024-11-21.