Security Digest · Vulnerability record · Known exploited
CVE-2024-21338: Microsoft Windows Kernel Exposed IOCTL with Insufficient Access Control Vulnerability
Exploited in the wild (CISA KEV). Windows Kernel Elevation of Privilege Vulnerability
CISA KEV · added 2024-03-04 CVSS 7.8 High EPSS 59.8% · p99
Should you act?
Exploited: patch now if you run it
CISA has confirmed exploitation in the wild. This signal is computed from CISA KEV, EPSS and CVSS data; it is not an editorial verdict.
- Yes, if you run Microsoft Windows. CISA added this CVE to its Known Exploited Vulnerabilities catalog on 2024-03-04, which means there is reliable evidence of exploitation in the wild. US federal agencies must remediate by 2024-03-25; treat that as the outer limit, not the target. CISA also lists it as known to be used in ransomware campaigns.
- EPSS 59.8%, percentile 99: FIRST’s model estimates a 59.8% chance of exploitation activity in the next 30 days, higher than 99% of all scored CVEs (very high). EPSS is a probability, not a verdict.
- Needs local access needed. Lower urgency for most teams unless an attacker could already run code on the machine.
What it is
Windows Kernel Elevation of Privilege Vulnerability
CISA’s summary
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.
Weakness type: CWE-822.
Product: Microsoft Windows · Assigned by: microsoft · Published: 2024-02-13
Affected and fixed versions
| Vendor | Product | Affected versions (per CVE record) |
|---|---|---|
| Microsoft | Windows 10 Version 1809 | 10.0.17763.0 < 10.0.17763.5458 |
| Microsoft | Windows 10 Version 1809 | 10.0.0 < 10.0.17763.5458 |
| Microsoft | Windows 10 Version 21H2 | 10.0.19043.0 < 10.0.19044.4046 |
| Microsoft | Windows 10 Version 22H2 | 10.0.19045.0 < 10.0.19045.4046 |
| Microsoft | Windows 11 version 21H2 | 10.0.0 < 10.0.22000.2777 |
| Microsoft | Windows 11 version 22H2 | 10.0.22621.0 < 10.0.22621.3155 |
| Microsoft | Windows 11 version 22H3 | 10.0.22631.0 < 10.0.22631.3155 |
| Microsoft | Windows 11 Version 23H2 | 10.0.22631.0 < 10.0.22631.3155 |
| Microsoft | Windows Server 2019 | 10.0.17763.0 < 10.0.17763.5458 |
| Microsoft | Windows Server 2019 (Server Core installation) | 10.0.17763.0 < 10.0.17763.5458 |
Severity scores
| Scored by | CVSS | Score | Vector |
|---|---|---|---|
| microsoft | 3.1 | 7.8 High | CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H/E:F/RL:O/RC:C |
- Attack vector: local access needed
- Attack complexity: low
- Privileges required: low (any account)
- User interaction: none
- Scope: unchanged
CVSS measures how bad a flaw is if exploited, not how likely exploitation is. Read it next to the exploitation data below.
Exploitation and urgency
- CISA KEV: added 2024-03-04; federal due date 2024-03-25. Known ransomware use: Known.
- CISA required action: Apply mitigations per vendor instructions or discontinue use of the product if mitigations are unavailable.
- CISA SSVC assessment: exploitation active, automatable no, technical impact total.
- FIRST EPSS (model of 2026-10-21): 59.81% probability of exploitation activity in the next 30 days; percentile 99.
Timeline
- — CVE record published by microsoft
- — Added to CISA’s Known Exploited Vulnerabilities catalog
- — CISA remediation deadline for US federal agencies
- — CVE record last updated
Sources and references
Original sources first. Version and fix details should always be confirmed against the vendor or project advisory.
Vendor and project advisories, patches
- Windows Kernel Elevation of Privilege Vulnerability msrc.microsoft.com
Vulnerability records
- CVE.org record CVE-2024-21338 cve.org
- NVD entry CVE-2024-21338 nvd.nist.gov
Government
Other references from the CVE record and advisory
- exploit-db.com exploit-db.com
- packetstorm.news packetstorm.news
- decoded.avast.io decoded.avast.io
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