CVE-2024-21309

Local privilege escalation via integer underflow

Published Jan 9, 2024 · Updated Jun 17, 2025

Integer underflow in a Windows kernel-mode driver in affected Windows 11 and Windows Server builds allows local users to gain SYSTEM privileges. Microsoft identifies the weakness but has not disclosed the affected driver, arithmetic operation, or attacker-controlled input. Exploitation requires low-privileged local access and no user interaction; success grants control at SYSTEM level.

CVSS severity7.8
High
EPSS probability0.76%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Integer underflow in a Windows kernel-mode driver in affected Windows 11 and Windows Server builds allows local users to gain SYSTEM privileges. Microsoft identifies the weakness but has not disclosed the affected driver, arithmetic operation, or attacker-controlled input. Exploitation requires low-privileged local access and no user interaction; success grants control at SYSTEM level.

The record

CVE
CVE-2024-21309
Published
Jan 9, 2024
Updated
Jun 17, 2025
Vendor
Microsoft
Product
Windows 11 version 21H2
Classifications
CWE-191, T1068
Attack vector
local
Privileges
authenticated

Timeline

How it unfolded

  1. Jan 9, 2024CVE publishedPublication date reported by the CVE source.
  2. Jun 17, 2025Record updatedLatest update available in the CVE record.

Exploitability

Present is not the same as exploitable

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Is a vulnerable build present?

Compare these published version ranges with your installed build and any vendor patches.

  1. Affected versionversion=10.0.0 <10.0.22000.2713

What conditions does exploitation require?

Attack vectorlocal
Required privilegesauthenticated

What is affected?

Microsoft · Windows 11 version 21H2version=10.0.0 <10.0.22000.2713
Microsoft · Windows Server 2022, 23H2 Edition (Server Core installation)version=10.0.25398.0 <10.0.25398.643
Microsoft · Windows 11 Version 22H3version=10.0.22631.0 <10.0.22631.3007
Microsoft · Windows 11 Version 23H2version=10.0.22631.0 <10.0.22631.3007
Microsoft · Windows 11, version 22H2version=10.0.22621.0 <10.0.22621.3007
Microsoft · Windows Server 2022version=10.0.20348.0 <10.0.20348.2227

Published CVSS scores

7.8Microsoft CorporationCVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H

CVSS describes severity. EPSS estimates exploitation probability.

Attacks

What attackers are doing with it

Daily unique IPs observed by Shadowserver honeypots for known exploited vulnerabilities (KEVs). Missing observations do not establish an absence of attacks.

Daily unique IPsNo honeypot observations are available for this CVE in the selected window.

No observations available

Sep 10, 2026Sep 16, 2026
Latest reporting daySep 16, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectorlocal
Privilegesauthenticated
Known exploitationUnconfirmed
Public exploitUnconfirmed

Weakness, pattern, technique

CWE-191Integer Underflow (Wrap or Wraparound)
T1068Exploitation for Privilege Escalation

Public exploit references

No public exploit references are available in this record.

Labels summarize the accepted research assessment. They do not indicate a test against your environment.

Technologies

Your stack

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Your stack

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