CVE-2025-59200: Windows 10 1507 Race Condition Vulnerability

CVE-2025-59200 Overview

CVE-2025-59200 is a race condition vulnerability in the Microsoft Windows Data Sharing Service Client. The flaw stems from concurrent execution using a shared resource with improper synchronization [CWE-73]. An unauthorized local attacker can exploit this timing window to perform spoofing on an affected system. Exploitation requires user interaction and local access, but successful attacks can lead to high integrity impact across a changed security scope. Microsoft published the vulnerability on October 14, 2025, and it affects supported versions of Windows 10, Windows 11, and Windows Server.

Critical Impact

A local attacker who wins the race window can spoof trusted operations performed by the Data Sharing Service, breaching integrity boundaries between user contexts on the same host.

Affected Products

• Microsoft Windows 10 (1507, 1607, 1809, 21H2, 22H2)
• Microsoft Windows 11 (22H2, 23H2, 24H2, 25H2)
• Microsoft Windows Server 2016, 2019, 2022, 2022 23H2, and 2025

Discovery Timeline

• 2025-10-14 - CVE-2025-59200 published to NVD
• 2025-10-17 - Last updated in NVD database

Technical Details for CVE-2025-59200

Vulnerability Analysis

The Data Sharing Service (dssvc.dll) is a Windows component that brokers data exchange between applications and user contexts. The vulnerability arises when multiple threads or processes access a shared resource without correct synchronization primitives. An attacker who interleaves operations precisely can manipulate the state observed by the service between validation and use. This Time-of-Check to Time-of-Use (TOCTOU) condition allows the attacker to substitute attacker-controlled data for trusted data. The result is spoofing of a privileged operation from a low-privilege context, with the scope changing beyond the initial security boundary.

Root Cause

The root cause is improper synchronization on a shared object handled by the Data Sharing Service Client. Concurrent access paths do not enforce atomicity between resource validation and resource consumption. This gap permits substitution or modification of the underlying resource during the race window, mapping to CWE-73 (External Control of File Name or Path) combined with race condition semantics.

Attack Vector

Exploitation requires local code execution and user interaction. A low-privileged attacker runs a process that repeatedly triggers Data Sharing Service Client operations while concurrently modifying the shared resource the service consults. When the attacker wins the timing window, the service acts on attacker-supplied data while attributing the action to the legitimate user or component. The attacker does not need prior credentials, but a victim must perform the triggering action. Verified public proof-of-concept code is not currently available for this vulnerability. Refer to the Microsoft Security Update CVE-2025-59200 advisory for vendor-specific technical details.

Detection Methods for CVE-2025-59200

Indicators of Compromise

• Unexpected child processes spawned by svchost.exe hosting the Data Sharing Service (dssvc).
• Rapid, repeated handle open and close operations against the same file or named object from a single non-system process.
• Files or registry keys consumed by the Data Sharing Service being modified by low-privileged processes immediately before service activity.

Detection Strategies

• Monitor process creation events where the parent is the Data Sharing Service host process and the child runs in an unexpected user context.
• Alert on high-frequency file system or object access loops targeting paths used by dssvc.dll, which often indicate race window probing.
• Correlate user interaction events with subsequent privileged operations by the Data Sharing Service to detect spoofed actions.

Monitoring Recommendations

• Enable Windows Security auditing for object access and process creation, and forward events to a centralized analytics platform.
• Track installation status of the October 2025 Microsoft security updates across all Windows endpoints and servers.
• Baseline normal Data Sharing Service behavior to surface anomalous concurrent access patterns from user-mode processes.

How to Mitigate CVE-2025-59200

Immediate Actions Required

• Apply the October 2025 Microsoft security updates referenced in the Microsoft Security Update CVE-2025-59200 advisory to all affected Windows 10, Windows 11, and Windows Server systems.
• Prioritize patching multi-user systems, jump hosts, and Remote Desktop Session Hosts where local attackers are more likely to interact with victim sessions.
• Restrict local logon rights and remove unnecessary interactive accounts on servers to reduce the local attack surface.

Patch Information

Microsoft has released security updates for all supported affected versions. Administrators should consult the Microsoft Security Update Guide for CVE-2025-59200 for KB article numbers corresponding to each Windows build and deploy the updates through Windows Update, WSUS, or Microsoft Intune.

Workarounds

• No official vendor workaround is documented; patching is the supported remediation path.
• As a defense-in-depth measure, enforce least privilege so that standard users cannot run arbitrary executables in shared session environments.
• Apply application control policies such as Windows Defender Application Control or AppLocker to block untrusted binaries that could drive the race condition.

# Verify the October 2025 cumulative update is installed on Windows endpoints
Get-HotFix | Sort-Object -Property InstalledOn -Descending | Select-Object -First 10

# Confirm Data Sharing Service is running in its expected state
Get-Service -Name DsSvc | Format-List Name,Status,StartType