CVE-2024-21338

Windows Kernel Elevation of Privilege Vulnerability

CVSS: 7.8Highscored by the publisher (CNA)
Exploited in the wild: Yes, in CISA KEV since 4 Mar 2024CISA deadline for US federal agencies: 25 Mar 2024known use in ransomware campaignspublic exploit code
EPSS: 62.2%chance of exploitation in the next 30 daystop 0.9% of scored CVEsFIRST score of 11 Nov 2026
Fix: Patch availablesee the advisories in the references
Published: 13 Feb 2024analysed here 12 Nov 2026

Do first. Apply mitigations per vendor instructions or discontinue use of the product if mitigations are unavailable. (CISA's required action for this KEV entry)

Summary

Triage

Exploitable: At runtime
Attack vector: local
Weakness: CWE-822 Common Weakness

The summary, impact and action text on this page are written by our AI analysis pipeline, or taken from the NVD description when a CVE was imported from NVD. They are not the vendor's wording: check them against the sources. A longer AI executive summary and technical analysis are generated for signed-in accounts on the Max plan.

Affected products

Product	Affected versions	Vendor says fixed in
Microsoft Windows 10 Version 1809	>= 10.0.17763.0 and < 10.0.17763.5458>= 10.0.0 and < 10.0.17763.5458Vendor says fixed in: not stated	Not stated by the vendor
Microsoft Windows 10 Version 21H2	>= 10.0.19043.0 and < 10.0.19044.4046Vendor says fixed in: not stated	Not stated by the vendor
Microsoft Windows 10 Version 22H2	>= 10.0.19045.0 and < 10.0.19045.4046Vendor says fixed in: not stated	Not stated by the vendor
Microsoft Windows 11 version 21H2	>= 10.0.0 and < 10.0.22000.2777Vendor says fixed in: not stated	Not stated by the vendor
Microsoft Windows 11 version 22H2	>= 10.0.22621.0 and < 10.0.22621.3155Vendor says fixed in: not stated	Not stated by the vendor
Microsoft Windows 11 version 22H3	>= 10.0.22631.0 and < 10.0.22631.3155Vendor says fixed in: not stated	Not stated by the vendor
Microsoft Windows 11 Version 23H2	>= 10.0.22631.0 and < 10.0.22631.3155Vendor says fixed in: not stated	Not stated by the vendor
Microsoft Windows Server 2019	>= 10.0.17763.0 and < 10.0.17763.5458Vendor says fixed in: not stated	Not stated by the vendor
Microsoft Windows Server 2019 (Server Core installation)	>= 10.0.17763.0 and < 10.0.17763.5458Vendor says fixed in: not stated	Not stated by the vendor
Microsoft Windows Server 2022	>= 10.0.20348.0 and < 10.0.20348.2322Vendor says fixed in: not stated	Not stated by the vendor
Microsoft Windows Server 2022, 23H2 Edition (Server Core installation)	>= 10.0.25398.0 and < 10.0.25398.709Vendor says fixed in: not stated	Not stated by the vendor

As published in the CVE Program record. A version outside these ranges is not a statement that it is unaffected — vendors sometimes understate a range, and distribution-backported builds carry upstream numbers that do not reflect what was patched into them.

Products named in our analysis

microsoft:windows_10_1809
microsoft:windows_10_21h2
microsoft:windows_10_22h2
microsoft:windows_11_21h2
microsoft:windows_11_22h2
microsoft:windows_11_23h2
microsoft:windows_server_2019
microsoft:windows_server_2022
microsoft:windows_server_2022_23h2

Fix and mitigation

WAF and other mitigations

Can a WAF block it? No. The attack needs local access to the machine, so a WAF is not on its path.

Also consider: patch

Based on the attack vector (local or physical access). We check Cloudflare, AWS, Google Cloud Armor and Azure; for Akamai, Imperva, Fastly, F5, ask your vendor.

Remediation steps (AI-written)

Step-by-step remediation is generated for accounts on the Max plan, for CVEs that match a technology in their stack. Add this technology to your stack to see the fix checklist.

Exploitation evidence

CISA KEV catalog: Listed since 4 Mar 2024. Known use in ransomware campaigns.
CISA due date: 25 Mar 2024, the remediation deadline for US federal agencies
CISA required action: Apply mitigations per vendor instructions or discontinue use of the product if mitigations are unavailable.
Public exploit code: Yes: 2 on Exploit-DB · 8 GitHub proofs of concept
CISA SSVC: exploitation active, automatable no, technical impact totalAssessed by CISA 12 Feb 2024 (SSVC 2.0.3). Exploitation is none, poc (public proof of concept) or active.

Exploit-DB

Microsoft Windows 11 - Kernel Privilege Escalationlocal, 22 Apr 2025
Microsoft Windows 10.0.17763.5458 - Kernel Privilege Escalationlocal, 2 Apr 2024

GitHub proofs of concept

and 4 more repositories

Listed so you can judge urgency, not as a recommendation to run anything. GitHub “proofs of concept” are unvetted: some are fake or carry malware. Exploit-DB marks the entries its staff verified.

Timeline

12 Feb 2024CISA SSVC assessment: exploitation active
13 Feb 2024Published2 days later
4 Mar 2024Added to CISA KEV (exploited in the wild)19 days later
25 Mar 2024CISA remediation due date (US federal agencies)21 days later
2 Apr 2024First public exploit or proof of concept8 days later
10 Aug 2026CVE record last updated861 days (about 2 years) later
12 Nov 2026Analysed by vulneraibility.com94 days (about 3 months) later

CVSS vector

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

Metric	Value	What it means
Attack vector	LocalLocal access required (shell, logged-in user).	Local access required (shell, logged-in user).
Attack complexity	LowRepeatable attack, no special conditions.	Repeatable attack, no special conditions.
Privileges required	LowThe attacker needs basic user privileges.	The attacker needs basic user privileges.
User interaction	NoneNo victim action needed.	No victim action needed.
Scope	UnchangedImpact stays within the vulnerable component.	Impact stays within the vulnerable component.
Confidentiality	HighTotal data disclosure possible.	Total data disclosure possible.
Integrity	HighComplete modification possible.	Complete modification possible.
Availability	HighFull outage possible.	Full outage possible.

Common questions

Is CVE-2024-21338 being exploited?

Yes. CVE-2024-21338 appears in CISA's Known Exploited Vulnerabilities catalog, which means exploitation in the wild has been confirmed and reported. Treat it as active rather than theoretical, and patch it ahead of higher-scoring vulnerabilities that carry no exploitation evidence.

How severe is CVE-2024-21338?

CVE-2024-21338 is rated High with a CVSS score of 7.8. Severity describes how bad exploitation would be, not how likely it is: pair it with exploitation evidence before deciding what to patch first.

Is there a patch for CVE-2024-21338?

Yes. A fix has been recorded for CVE-2024-21338. The vendor advisory is the authority on the exact fixed version — apply it from there rather than from a summary.

What does CVE-2024-21338 affect?

CVE-2024-21338 affects microsoft:windows_10_1809, microsoft:windows_10_21h2, microsoft:windows_10_22h2, microsoft:windows_11_21h2, and 5 further products or versions. Confirm the exact affected versions against the vendor advisory before deciding you are exposed.

Exploitation status reflects CISA's KEV catalog as we last synced it. Check the catalog directly.

References

NVD CVE.org CVE Details Source

5 references in the CVE record, grouped by the tags the record gives them.

Patches (1)

msrc.microsoft.com /update-guide/vulnerability/CVE-2024-21338

Where the data on this page comes from

CVE List (CVE.org): description, affected versions, references; CVE Terms of Use
NVD: CVSS and CPE data
CISA KEV catalog: exploitation, date added, due date
CISA Vulnrichment (ADP): SSVC decision points
FIRST EPSS: exploit probability and percentile
Exploit-DB: published exploits
PoC-in-GitHub: GitHub repositories that claim a proof of concept

Summary, impact and triage tags: written by our AI analysis pipeline from the sources above. Check them against the sources.

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