CVE-2026-32074: Windows Projected File System Escalation

CVE-2026-32074 Overview

CVE-2026-32074 is a double free vulnerability affecting the Windows Projected File System (ProjFS) that allows an authorized attacker to elevate privileges locally. This memory corruption flaw (CWE-415) enables attackers with local access to escalate their privileges on affected Windows systems by exploiting improper memory management within the ProjFS component.

Critical Impact

An authenticated local attacker can exploit this double free condition to gain elevated privileges, potentially achieving SYSTEM-level access on affected Windows systems.

Affected Products

• Windows Projected File System (ProjFS)
• Windows operating systems with ProjFS component enabled
• Systems utilizing virtualized file system projections

Discovery Timeline

• April 14, 2026 - CVE-2026-32074 published to NVD
• April 14, 2026 - Last updated in NVD database

Technical Details for CVE-2026-32074

Vulnerability Analysis

The vulnerability resides in the Windows Projected File System (ProjFS), a component that allows user-mode applications to project hierarchical data into the file system. The double free condition occurs when memory is freed twice during file system operations, leading to memory corruption that can be exploited for privilege escalation.

Double free vulnerabilities are particularly dangerous because they can corrupt memory management structures, allowing attackers to potentially overwrite critical data structures or function pointers. In the context of ProjFS, which operates with elevated privileges to manage virtualized file system projections, successful exploitation can lead to complete system compromise.

The local attack vector requires the attacker to have prior authentication on the target system. Once authenticated, the attacker can trigger the vulnerable code path without requiring user interaction, making this a straightforward privilege escalation attack for adversaries who have already gained initial access.

Root Cause

The root cause of CVE-2026-32074 is a double free condition (CWE-415) in the Windows Projected File System component. This occurs when the same memory region is passed to a deallocation function twice, corrupting heap metadata and creating conditions that can be leveraged for arbitrary code execution or privilege escalation.

Double free vulnerabilities typically arise from:

• Missing or incorrect tracking of memory allocation state
• Error handling paths that free memory already released in the normal execution path
• Race conditions between concurrent operations accessing the same memory region
• Improper reference counting mechanisms

Attack Vector

The attack requires local access to the target system with low privileges. An attacker must be authenticated but does not require administrative rights to initiate the exploit. The attack does not require any user interaction, meaning once an attacker has established a foothold on the system, they can independently trigger the vulnerability.

Exploitation involves triggering specific ProjFS operations that cause the double free condition. By carefully crafting the timing and sequence of file system operations, an attacker can manipulate the heap state to gain control over execution flow, ultimately escalating privileges to SYSTEM level.

The vulnerability mechanism involves memory corruption in the ProjFS driver during file projection operations. When specific conditions are met, the driver incorrectly frees memory that has already been deallocated, corrupting heap structures. Technical details are available in the Microsoft Security Advisory.

Detection Methods for CVE-2026-32074

Indicators of Compromise

• Unusual crash events or Blue Screen of Death (BSOD) incidents related to ProjFS driver components
• Unexpected privilege escalation events from low-privileged accounts
• Anomalous file system operations targeting projected file system mount points
• Memory corruption artifacts in Windows Event Logs related to PrjFlt.sys or related drivers

Detection Strategies

• Monitor for heap corruption events and memory access violations in kernel-mode drivers
• Implement endpoint detection rules for suspicious ProjFS driver interactions from non-standard processes
• Deploy behavioral analysis to detect privilege escalation attempts following file system operations
• Utilize SentinelOne's behavioral AI engine to identify exploitation patterns associated with double free attacks

Monitoring Recommendations

• Enable Windows Event Log monitoring for kernel driver faults and system stability events
• Configure SentinelOne agents to alert on suspicious privilege transitions from user-mode to kernel-mode
• Monitor process creation events for unexpected SYSTEM-level processes spawned from lower-privileged contexts
• Implement file integrity monitoring on critical system directories that may be targeted post-exploitation

How to Mitigate CVE-2026-32074

Immediate Actions Required

• Apply the latest Windows security updates from Microsoft immediately
• Review systems for signs of exploitation, particularly any unauthorized privilege escalation
• Restrict local access to systems where ProjFS is enabled to trusted users only
• Consider temporarily disabling ProjFS if not required for business operations until patching is complete

Patch Information

Microsoft has released a security update to address this vulnerability. Administrators should consult the Microsoft Security Advisory for CVE-2026-32074 for detailed patch information, affected product versions, and deployment guidance. Apply the security update through Windows Update, WSUS, or Microsoft Update Catalog as appropriate for your environment.

Workarounds

• If patching is not immediately possible, consider disabling the Windows Projected File System feature if it is not required
• Limit local user access to systems with ProjFS enabled to reduce the attack surface
• Implement application whitelisting to prevent unauthorized executables from running
• Deploy enhanced monitoring and logging on systems where immediate patching is not feasible

# Check if Projected File System is enabled (PowerShell)
Get-WindowsOptionalFeature -Online -FeatureName Client-ProjFS

# Disable Projected File System if not required (requires admin privileges)
Disable-WindowsOptionalFeature -Online -FeatureName Client-ProjFS -NoRestart

# Verify the feature has been disabled
Get-WindowsOptionalFeature -Online -FeatureName Client-ProjFS | Select-Object State