CVE-2026-50674: Windows USB Print Driver Privilege Escalation

CVE-2026-50674 Overview

CVE-2026-50674 is a use-after-free vulnerability [CWE-416] in the Windows USB Print Driver. An authorized local attacker can trigger the flaw to elevate privileges on an affected system. Microsoft published the advisory on July 14, 2026. The issue requires local access and low privileges, but attack complexity is high because exploitation depends on winning a race or manipulating driver object lifecycle timing. Successful exploitation yields high impact to confidentiality, integrity, and availability.

Critical Impact
A local authenticated user can execute code in kernel context through the Windows USB Print Driver, granting SYSTEM-level privileges and full control over the affected host.

Affected Products

Microsoft Windows (USB Print Driver component)
Refer to the Microsoft Security Update Guide for the authoritative list of affected Windows versions and builds
Systems with the Windows USB Print Driver enabled

Discovery Timeline

2026-07-14 - CVE-2026-50674 published to NVD
2026-07-15 - Last updated in NVD database

Technical Details for CVE-2026-50674

Vulnerability Analysis

The vulnerability is a use-after-free condition in the Windows USB Print Driver. The driver frees a kernel object but retains a reference that is later dereferenced. An attacker who controls allocation and freeing timing can substitute a crafted object at the freed address. When the driver reuses the stale pointer, it operates on attacker-controlled data in kernel memory.

Because the flawed code path resides in a kernel-mode driver, successful exploitation yields SYSTEM privileges. The attacker must already be authenticated on the target machine and must interact with the USB print stack, either directly or through a user-mode print client that reaches the vulnerable ioctl paths.

Root Cause

The root cause is improper object lifetime management in the USB Print Driver [CWE-416]. Reference counts or lock semantics fail to prevent access to a freed allocation. See the Microsoft advisory for component-level technical details.

Attack Vector

The attack vector is local. An authenticated user issues a sequence of driver requests that trigger the free and subsequent reuse of a kernel object. High attack complexity reflects the race condition or heap grooming required to reliably place controlled data in the freed slot. No user interaction is required.

Microsoft has not published a proof of concept and there are no reports of exploitation in the wild. The EPSS forecast places short-term exploitation likelihood in a low percentile range.

Detection Methods for CVE-2026-50674

Indicators of Compromise

Unexpected SYSTEM-level processes spawned from user sessions shortly after USB print activity
Kernel crashes or bugchecks referencing the USB print driver stack in WER or Minidump output
Loading of unsigned or unusual DLLs into the print spooler process (spoolsv.exe) following device enumeration

Detection Strategies

Monitor for anomalous IOCTL patterns and rapid open/close cycles against USB print driver device objects
Correlate local privilege escalation telemetry with recent USB device insertion events on endpoints
Alert on child processes of print-related services running as NT AUTHORITY\SYSTEM that were initiated by standard user sessions

Monitoring Recommendations

Enable Windows kernel and driver load event logging and forward to a central SIEM for correlation
Track Windows Update patch compliance across endpoints to identify hosts missing the Microsoft fix
Monitor Event ID 41 and 1001 (kernel crash and Windows Error Reporting) for driver faults in the USB print stack

How to Mitigate CVE-2026-50674

Immediate Actions Required

Apply the Microsoft security update referenced in the MSRC advisory for CVE-2026-50674 as soon as testing permits
Inventory endpoints and servers with the USB Print Driver enabled and prioritize multi-user systems
Restrict local logon rights on shared workstations to reduce the pool of accounts that can trigger the flaw

Patch Information

Microsoft addressed CVE-2026-50674 in the July 2026 security update cycle. Consult the Microsoft Security Update Guide for the specific KB articles, affected build ranges, and superseding updates that apply to your Windows deployment.

Workarounds

Disable the Windows USB Print Driver on systems that do not require local USB printing
Enforce Group Policy that blocks installation of removable USB print devices on high-value hosts
Limit interactive logon on print servers and shared endpoints until patches are deployed

bash

# Configuration example: block USB printer device installation via Group Policy
# Computer Configuration > Administrative Templates > System > Device Installation >
#   Device Installation Restrictions > Prevent installation of devices using drivers
#   that match these device setup classes
#
# Add the Printer setup class GUID:
#   {4d36e979-e325-11ce-bfc1-08002be10318}