CVE-2024-21338
KEVRansomware UseMicrosoft Windows Kernel Exposed IOCTL with Insufficient Access Control Vulnerability
Description
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.
Windows Kernel Elevation of Privilege Vulnerability
CVSS 3.1 vector
CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:HPublishedFeb 13, 2024
Last modifiedAug 10, 2026
Added to KEVMar 4, 2024
Remediation dueMar 25, 2024
References
- msrc.microsoft.com/update-guide/vulnerability/CVE-2024-21338PatchVendor Advisory
- decoded.avast.io/janvojtesek/lazarus-and-the-fudmodule-rootkit-beyond-byovd-with-an-admin-to-kernel-zero-day/ExploitTechnical Description
- packetstorm.news/files/id/190586/ExploitVDB Entry
- exploit-db.com/exploits/52275ExploitVDB Entry
- cisa.gov/known-exploited-vulnerabilities-catalog?field_cve=CVE-2024-21338US Government Resource
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Risk assessment · Critical
Actively exploited and used by ransomware crews. Patch immediately.
- Exploitation
- Confirmed in the wild (CISA KEV)
- Federal remediation deadline
- Overdue by 945 days
- Ransomware
- Used in known ransomware campaigns
- CVSS
- 7.8 HIGH
- EPSS (30-day exploit probability)
- 59.8% · top 1% of all CVEs
- Weakness
- CWE-822
Recommended actions
- 1.Apply mitigations per vendor instructions or discontinue use of the product if mitigations are unavailable.
- 2.Treat as emergency change: patch or isolate internet-facing instances first.
- 3.Hunt for compromise: review logs for the disclosure window, not just from the patch date.
- 4.Verify offline/immutable backups and segment the affected systems. This flaw is used for ransomware initial access.
Assessment is derived automatically from the live signals above; verify against your own asset inventory.