CVE & CISA-KEV Catalog

CVE-2024-21338

HIGHCISA KEVEPSS 99th pctl
7.8
CVSS v3
NVD

Description

Windows Kernel Elevation of Privilege Vulnerability

How to fix

Remediation Available
Windows 10 Version 1809Windows
Install:KB5034768Microsoft
Windows 10 Version 21H2Windows
Install:KB5034763Microsoft
Windows 10 Version 22H2Windows
Install:KB5034763Microsoft
Windows 11 Version 22H2Windows
Install:KB5034765Microsoft
Windows 11 Version 23H2Windows
Install:KB5034765Microsoft
Windows 11 version 21H2Windows
Install:KB5034766Microsoft
Windows Server 2019Windows
Install:KB5034768Microsoft
Windows Server 2019 (Server Core installation)Windows
Install:KB5034768Microsoft
Windows Server 2022Windows
Install:KB5034770Microsoft
Windows Server 2022 (Server Core installation)Windows
Install:KB5034770Microsoft
Windows Server 2022, 23H2 Edition (Server Core installation)Windows
Install:KB5034769Microsoft

TridentStack Control can deploy fixes like this automatically across your Windows, macOS, and Linux fleet. See how it works

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
IntegrityHigh
AvailabilityHigh

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

Exploit Intelligence

59.81%probability of exploitation in 30 days
99thpercentile

Very high risk: more likely to be exploited than 99% of all known CVEs.

Known Exploited Vulnerability (CISA KEV)

Microsoft Windows Kernel Exposed IOCTL with Insufficient Access Control Vulnerability

Microsoft Windows Kernel contains an exposed IOCTL with insufficient access control vulnerability within the IOCTL (input and output control) dispatcher in appid.sys that allows a local attacker to achieve privilege escalation.

Apply mitigations per vendor instructions or discontinue use of the product if mitigations are unavailable.

Remediation due: 2024-03-25

Associated with ransomware campaigns

References

Related Vulnerabilities

Other CWE-822 (Untrusted Pointer Dereference) vulnerabilities, ordered by exploit likelihood. View all

CVESeverityCVSSEPSSExploitedFix
CVE-2023-21768High7.865%-Fix
CVE-2024-35250High7.825%KEVFix
CVE-2023-29360High8.422%KEVFix
CVE-2023-36033High7.812%KEVFix
CVE-2025-50165Critical9.89.5%-Fix
CVE-2019-13334High7.86.8%--

Common questions

How do I fix CVE-2024-21338?

Published advisories record a fix for 11 affected products. The "How to fix" section on this page lists the fixed version and source advisory for each one, so apply the entry matching what you actually run.

Is CVE-2024-21338 being actively exploited?

Yes. CVE-2024-21338 is listed in the CISA Known Exploited Vulnerabilities catalog, which means exploitation has been observed in the wild. CISA has also linked it to known ransomware campaigns. US federal agencies were required to remediate it by 2024-03-25. Treat it as a priority whatever its CVSS score says.

How severe is CVE-2024-21338?

CVE-2024-21338 has a CVSS v3 base score of 7.8, rated high. CVSS rates the technical impact if the vulnerability is exploited, not how likely that is, so weigh it alongside the exploit-prediction score when you decide what to patch first.

What does CVE-2024-21338 affect?

Published advisories record a fix for Windows 10 Version 1809 (Windows), Windows 10 Version 21H2 (Windows), Windows 10 Version 22H2 (Windows), Windows 11 Version 22H2 (Windows), and 7 more. Only products with a sourced advisory are listed, so treat this as what we can cite rather than a complete inventory.

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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 2026-08-10.