CVE-2026-50375 Overview
CVE-2026-50375 is a heap-based buffer overflow vulnerability in the Windows DirectX graphics subsystem. An authenticated local attacker can trigger the overflow to corrupt kernel-mode heap memory and elevate privileges to SYSTEM. Microsoft published the advisory on July 14, 2026, covering supported Windows client and server releases. The flaw is classified under [CWE-122] Heap-based Buffer Overflow and affects the confidentiality, integrity, and availability of the target host.
Critical Impact
A low-privileged local user can execute code in the context of the Windows kernel, enabling full compromise of the affected system.
Affected Products
- Microsoft Windows 10 (1809, 21H2, 22H2) on x86, x64, and ARM64
- Microsoft Windows 11 (24H2, 25H2, 26H1) on x64 and ARM64
- Microsoft Windows Server 2019, 2022, and 2025
Discovery Timeline
- 2026-07-14 - Microsoft publishes advisory for CVE-2026-50375
- 2026-07-14 - CVE-2026-50375 published to NVD
- 2026-07-20 - Last updated in NVD database
Technical Details for CVE-2026-50375
Vulnerability Analysis
The vulnerability resides in the DirectX component of Windows, which exposes kernel-mode graphics interfaces to user-mode processes. A heap-based buffer overflow ([CWE-122]) occurs when the affected code path writes attacker-controlled data past the boundary of an allocated kernel heap buffer. Because DirectX drivers run within the Windows kernel, corruption of adjacent pool structures can be leveraged to overwrite function pointers or object headers.
Successful exploitation results in code execution at the kernel level, giving the attacker SYSTEM privileges on the compromised endpoint. The issue requires local access and low privileges, but no user interaction, which makes it a strong candidate for post-compromise privilege escalation in multi-stage intrusions.
Root Cause
The underlying defect is improper bounds validation on data supplied through a DirectX IOCTL or graphics kernel API. When the kernel copies attacker-controlled input into a fixed-size pool allocation, it fails to enforce the buffer size, allowing adjacent kernel memory to be overwritten.
Attack Vector
An attacker must first obtain the ability to execute code as a standard local user, for example through a phishing payload, a compromised service, or an existing foothold. The attacker then invokes the vulnerable DirectX interface with a crafted request to corrupt kernel heap memory. Chained with an initial access vector, this flaw is well suited to converting a limited user compromise into full domain-relevant access on servers or workstations. Refer to the Microsoft Security Update CVE-2026-50375 advisory for component-level details.
Detection Methods for CVE-2026-50375
Indicators of Compromise
- Unexpected bug checks (BSOD) referencing DirectX kernel modules such as dxgkrnl.sys or dxgmms2.sys, especially on hosts running non-graphics workloads.
- Standard user processes spawning children that run as NT AUTHORITY\SYSTEM shortly after invoking graphics APIs.
- Creation of new services, scheduled tasks, or local administrator accounts by processes that recently interacted with DirectX kernel interfaces.
Detection Strategies
- Hunt for non-graphical processes issuing DeviceIoControl calls against \\.\DXGKrnl or related device objects.
- Correlate crash dumps in dxgkrnl.sys with subsequent privilege changes on the same host within a short time window.
- Baseline DirectX API usage per process and alert on anomalous callers such as command-line utilities, scripting hosts, or newly deployed binaries.
Monitoring Recommendations
- Enable kernel-mode crash dump collection and forward WER reports to a central SIEM for triage.
- Monitor Windows event logs for token elevation events (Event ID 4672) tied to processes that were previously low-privileged.
- Track deployment status of the July 2026 Microsoft security updates across all Windows 10, Windows 11, and Windows Server assets.
How to Mitigate CVE-2026-50375
Immediate Actions Required
- Apply the July 2026 Microsoft security update for CVE-2026-50375 to all affected Windows client and server systems.
- Prioritize patching multi-user hosts such as Remote Desktop Session Hosts, VDI infrastructure, and terminal servers where local access is broadly available.
- Audit local accounts and remove unnecessary interactive logon rights to reduce the attacker population capable of triggering the flaw.
Patch Information
Microsoft has released fixes through its standard update channels. Consult the Microsoft Security Update CVE-2026-50375 advisory for KB article numbers and product-specific build versions. Deploy via Windows Update, Windows Server Update Services (WSUS), Microsoft Intune, or Configuration Manager according to your patch management process.
Workarounds
- No official workaround is documented by Microsoft. Patching is the required remediation.
- Restrict local and interactive logon rights on servers to trusted administrators until patches are deployed.
- Enforce application allowlisting to limit which binaries unprivileged users can execute against DirectX kernel interfaces.
# Verify installed updates on a Windows host (PowerShell)
Get-HotFix | Sort-Object -Property InstalledOn -Descending | Select-Object -First 20
# Confirm the affected DirectX kernel driver version
Get-Item C:\Windows\System32\drivers\dxgkrnl.sys | Select-Object VersionInfo
Disclaimer: This content was generated using AI. While we strive for accuracy, please verify critical information with official sources.
