CVE-2025-29838: Windows 11 24H2 Privilege Escalation Flaw

CVE-2025-29838 Overview

CVE-2025-29838 is a null pointer dereference vulnerability [CWE-476] in Windows Drivers affecting Microsoft Windows 11 24H2 and Windows Server 2025. The flaw allows a local, low-privileged attacker to elevate privileges on affected systems. Microsoft published the advisory on May 13, 2025, and the vulnerability carries a CVSS 3.1 base score of 7.0. Successful exploitation impacts confidentiality, integrity, and availability of the target host.

Critical Impact
A local attacker with low privileges can trigger a null pointer dereference in a Windows driver to gain elevated privileges, giving them the ability to install programs, modify system data, and create new accounts with full user rights.

Affected Products

Microsoft Windows 11 24H2 (x64 and ARM64)
Microsoft Windows Server 2025
Systems running vulnerable Windows Drivers component

Discovery Timeline

2025-05-13 - Microsoft releases security update for CVE-2025-29838
2025-05-13 - CVE-2025-29838 published to NVD
2026-06-17 - Last updated in NVD database

Technical Details for CVE-2025-29838

Vulnerability Analysis

The vulnerability resides in a Windows Drivers component shipped with Windows 11 24H2 and Windows Server 2025. When the driver processes certain input from a local user-mode caller, it dereferences a pointer without first validating whether it references a valid kernel object. This condition falls under CWE-476, Null Pointer Dereference.

In kernel context, dereferencing a null or attacker-controllable pointer can be leveraged beyond a simple crash. On modern Windows builds, techniques that map the null page are blocked by design, but incomplete pointer validation combined with adjacent kernel state can allow an attacker to influence execution flow. The attack complexity is high, indicating that exploitation requires specific timing, configuration, or race conditions to succeed reliably.

Successful exploitation yields SYSTEM-level privileges from a low-privileged local session. This gives an attacker full control over the affected host, including the ability to disable security controls, extract credentials, and persist on the system.

Root Cause

The root cause is missing validation of a pointer inside a kernel-mode driver dispatch or ioctl handler. The driver assumes an object or structure reference is non-null when servicing a request from user mode, and proceeds to read from or write through that pointer.

Attack Vector

Exploitation requires local access with low privileges (PR:L) and no user interaction. An attacker with an existing foothold, whether through phishing, a compromised service account, or a prior initial-access vulnerability, issues crafted IOCTLs or API calls to the vulnerable driver. The high attack complexity indicates that exploitation is not straightforward and typically requires precise conditions.

Refer to the Microsoft Security Update Guide for CVE-2025-29838 for authoritative technical details.

Detection Methods for CVE-2025-29838

Indicators of Compromise

Unexpected SYSTEM processes spawned from user-context parent processes such as explorer.exe or cmd.exe
Bugcheck events (BSOD) referencing the vulnerable driver, especially stop code 0x00000050 (PAGE_FAULT_IN_NONPAGED_AREA) or 0x0000003B (SYSTEM_SERVICE_EXCEPTION)
Creation of new local administrator accounts or modification of privileged group membership shortly after suspicious driver interaction
Loading of unsigned or newly dropped helper binaries by low-privileged users prior to privilege escalation events

Detection Strategies

Monitor Windows Event Log channels System and Microsoft-Windows-Kernel-General for repeated driver crashes on Windows 11 24H2 and Server 2025 hosts
Detect abnormal DeviceIoControl call patterns from non-administrative processes against kernel drivers using EDR telemetry
Alert on token manipulation and process integrity level changes indicative of local privilege escalation
Correlate crash dumps with subsequent privilege escalation activity on the same host within short time windows

Monitoring Recommendations

Enable kernel-mode crash dump collection on production endpoints and forward .dmp metadata to a centralized SIEM
Baseline driver load events (Sysmon Event ID 6) and alert on anomalous or newly introduced drivers
Track post-exploitation behaviors, including credential dumping, service creation, and scheduled task registration, following any driver crash event

How to Mitigate CVE-2025-29838

Immediate Actions Required

Apply the May 2025 Microsoft security update for CVE-2025-29838 to all Windows 11 24H2 and Windows Server 2025 systems
Prioritize patching on multi-user systems, jump hosts, and terminal servers where local privilege escalation risk is highest
Audit local accounts and remove unnecessary interactive logon rights to reduce the pool of potential attackers
Validate that endpoint protection agents are active and reporting on all in-scope hosts

Patch Information

Microsoft addressed CVE-2025-29838 in the May 13, 2025 security update. Deploy the update through Windows Update, WSUS, or Microsoft Intune. Full details are available in the Microsoft Security Update Guide.

Workarounds

No official vendor workaround is published; patching is the required remediation
Enforce principle of least privilege and restrict local logon on sensitive systems until patches are deployed
Enable Windows Defender Application Control (WDAC) or AppLocker policies to limit execution of unapproved local binaries that could stage the exploit
Maintain up-to-date kernel driver blocklists via the Microsoft Vulnerable Driver Blocklist feature

bash

# Verify patch deployment status on Windows hosts
Get-HotFix | Where-Object { $_.InstalledOn -ge (Get-Date '2025-05-13') }

# Confirm the Microsoft Vulnerable Driver Blocklist is enabled
Get-CimInstance -ClassName Win32_DeviceGuard | 
    Select-Object -ExpandProperty SecurityServicesConfigured