CVE-2026-32150: Function Discovery Service Race Condition

CVE-2026-32150 Overview

CVE-2026-32150 is a race condition vulnerability in Microsoft Windows Function Discovery Service (fdwsd.dll) that allows an authorized local attacker to elevate privileges. The vulnerability stems from concurrent execution using a shared resource with improper synchronization, classified as CWE-362. This type of flaw enables attackers with low-privilege access to exploit timing windows during resource access to gain elevated system privileges.

Critical Impact

Local privilege escalation through race condition exploitation allows attackers with basic user access to gain elevated system privileges, potentially leading to full system compromise.

Affected Products

• Microsoft Windows Function Discovery Service (fdwsd.dll)
• Windows operating systems with Function Discovery Service enabled

Discovery Timeline

• April 14, 2026 - CVE-2026-32150 published to NVD
• April 14, 2026 - Last updated in NVD database

Technical Details for CVE-2026-32150

Vulnerability Analysis

This vulnerability exists in the Windows Function Discovery Service, specifically within the fdwsd.dll component. The Function Discovery Service is responsible for discovering and enumerating devices and services on the network, making it a privileged system service that runs with elevated permissions.

The race condition occurs when the service handles concurrent access to shared resources without proper synchronization mechanisms. An attacker with local access and low-level privileges can exploit the timing window between the check and use of a shared resource (Time-of-Check Time-of-Use or TOCTOU pattern) to manipulate the service's execution flow.

Successful exploitation requires the attacker to win the race condition, which introduces complexity to the attack. However, race conditions can often be reliably triggered through repeated attempts or by manipulating system timing through CPU load or other techniques.

Root Cause

The root cause is improper synchronization when the Function Discovery Service accesses shared resources. The service fails to implement adequate locking mechanisms or atomic operations when multiple threads or processes access the same resource concurrently. This allows an attacker to modify the state of the shared resource between the time it is checked and the time it is used, leading to unexpected behavior and privilege escalation.

Attack Vector

The attack vector is local, meaning the attacker must have authenticated access to the target system. The attack proceeds as follows:

1. The attacker identifies the vulnerable code path in fdwsd.dll where improper synchronization occurs
2. The attacker crafts a payload or technique to race against the legitimate service operation
3. By precisely timing their actions, the attacker modifies the shared resource state after the security check but before the service uses the resource
4. When the service proceeds with the operation using the attacker-controlled data, code execution occurs in the context of the privileged service
5. The attacker gains elevated privileges on the system

The vulnerability can be exploited by manipulating file system objects, registry keys, or memory structures that the Function Discovery Service accesses without proper synchronization. For detailed technical information, refer to the Microsoft Security Update Guide.

Detection Methods for CVE-2026-32150

Indicators of Compromise

• Unusual process spawning from fdwsd.dll or the Function Discovery Service
• Repeated rapid file or registry access patterns targeting Function Discovery Service resources
• Unexpected privilege escalation events from low-privilege user accounts
• Anomalous timing patterns in system calls related to the Function Discovery Service

Detection Strategies

• Monitor for suspicious process behavior involving the Function Discovery Service using endpoint detection and response (EDR) tools
• Implement behavioral analysis to detect race condition exploitation attempts characterized by rapid repeated operations
• Enable Windows Event Log auditing for privilege escalation events and service anomalies
• Deploy SentinelOne's real-time behavioral AI to detect exploitation patterns associated with race condition attacks

Monitoring Recommendations

• Configure Windows Security Event logging to capture process creation and privilege changes
• Monitor for rapid sequential access to Function Discovery Service related files and registry keys
• Implement application whitelisting to prevent unauthorized code execution from exploited services
• Use SentinelOne's Singularity platform for continuous monitoring of suspicious service behavior

How to Mitigate CVE-2026-32150

Immediate Actions Required

• Apply the latest Microsoft security updates addressing CVE-2026-32150 immediately
• Review and restrict local user access to minimize the attack surface for privilege escalation
• Enable enhanced monitoring for the Function Discovery Service until patches are applied
• Consider temporarily disabling the Function Discovery Service if not required for business operations

Patch Information

Microsoft has released a security update to address this vulnerability. Organizations should apply the patch available through Windows Update or the Microsoft Security Update Guide. The patch implements proper synchronization mechanisms to prevent the race condition from being exploited.

Workarounds

• Disable the Function Discovery Service (fdwsd) if it is not required for business operations via services.msc or Group Policy
• Implement strict local access controls to limit which users can interact with system services
• Deploy application control policies to prevent unauthorized code execution
• Use network segmentation to limit lateral movement if a system is compromised

# Disable Function Discovery Service (if not required)
sc config fdwsd start= disabled
sc stop fdwsd

# Verify service status
sc query fdwsd