CVE-2025-50177: Windows 10 1507 Use-After-Free Vulnerability

CVE-2025-50177 Overview

CVE-2025-50177 is a use-after-free vulnerability in Windows Message Queuing (MSMQ) that allows an unauthorized attacker to execute arbitrary code over a network. This memory corruption flaw exists in the MSMQ service, a core Windows component that enables asynchronous communication between distributed applications. When exploited, this vulnerability can grant attackers complete control over affected systems without requiring any user interaction or prior authentication.

Critical Impact

Successful exploitation allows remote code execution with no authentication required, potentially compromising confidentiality, integrity, and availability of enterprise Windows systems and servers.

Affected Products

• Microsoft Windows 10 (versions 1507, 1607, 1809, 21H2, 22H2)
• Microsoft Windows 11 (versions 22H2, 23H2, 24H2)
• Microsoft Windows Server 2008, 2008 R2, 2012, 2012 R2, 2016, 2019, 2022, 2022 23H2, 2025

Discovery Timeline

• August 12, 2025 - CVE-2025-50177 published to NVD
• August 19, 2025 - Last updated in NVD database

Technical Details for CVE-2025-50177

Vulnerability Analysis

This use-after-free vulnerability (CWE-362) occurs in the Windows Message Queuing service due to a race condition in memory management operations. When the MSMQ service processes specially crafted network requests, a timing window exists where memory can be freed while still being referenced. An attacker can exploit this race condition to cause the service to access deallocated memory, potentially allowing arbitrary code execution in the context of the MSMQ service.

The vulnerability requires no user interaction and can be triggered remotely over the network. While exploitation requires winning a race condition, successful attacks can result in complete system compromise with the ability to read, modify, or delete data, install malware, or pivot to other systems on the network.

Root Cause

The root cause stems from a race condition (CWE-362) in how Windows Message Queuing handles concurrent operations on memory objects. When multiple threads access shared resources without proper synchronization, a time-of-check to time-of-use (TOCTOU) condition can occur. This allows an attacker to manipulate the timing of operations such that memory is freed in one context while another context still holds a reference to it, leading to the use-after-free condition.

Attack Vector

The attack is network-based and targets the MSMQ service listening on TCP port 1801. An attacker can send specially crafted messages to the MSMQ service designed to trigger the race condition. The attack does not require any form of authentication or user privileges on the target system.

The exploitation mechanism involves:

1. Sending malicious MSMQ messages to the target system's Message Queuing service
2. Timing the requests to trigger the race condition in memory handling
3. Causing memory to be freed while references to it still exist
4. Manipulating the freed memory to achieve code execution

Due to the race condition nature of this vulnerability, exploitation complexity is higher than typical memory corruption flaws, requiring precise timing and potentially multiple attempts. However, in environments where MSMQ is exposed to untrusted networks, the risk remains significant.

Detection Methods for CVE-2025-50177

Indicators of Compromise

• Unexpected crashes or restarts of the Message Queuing service (mqsvc.exe)
• Anomalous network traffic on TCP port 1801 from external or untrusted sources
• Unusual child processes spawned by the MSMQ service process
• Memory access violations or exception events logged in Windows Event Logs related to mqsvc.exe

Detection Strategies

• Monitor for abnormal MSMQ network traffic patterns, particularly high-frequency connection attempts or malformed message structures
• Implement endpoint detection rules to identify suspicious behavior from the mqsvc.exe process, including unexpected code execution or privilege escalation
• Deploy network intrusion detection signatures to identify exploitation attempts targeting MSMQ services
• Enable and review Windows Security Event logs for service crashes, access violations, and unexpected process creation

Monitoring Recommendations

• Configure alerting for MSMQ service failures or unexpected restarts in your SIEM platform
• Establish baseline network behavior for MSMQ communications and alert on deviations
• Monitor for process injection or memory manipulation techniques targeting system services
• Review audit logs for authentication attempts and access to message queues from unexpected sources

How to Mitigate CVE-2025-50177

Immediate Actions Required

• Apply the latest Microsoft security updates as soon as possible from the Microsoft Security Update Guide
• If MSMQ is not required, disable the Message Queuing service to eliminate the attack surface entirely
• Restrict network access to TCP port 1801 using firewall rules to block untrusted traffic
• Isolate systems running MSMQ from untrusted network segments until patches are applied

Patch Information

Microsoft has released security updates to address this vulnerability. Organizations should consult the Microsoft CVE-2025-50177 Advisory for detailed patch information and download links specific to their Windows versions. Patches are available for all supported Windows client and server versions affected by this vulnerability.

Workarounds

• Disable the Windows Message Queuing service if it is not required for business operations using Set-Service -Name MSMQ -StartupType Disabled
• Block TCP port 1801 at network perimeter firewalls to prevent external exploitation attempts
• Implement network segmentation to isolate MSMQ servers from untrusted network zones
• Apply Windows Firewall rules to restrict MSMQ access to only trusted internal systems

# PowerShell: Disable MSMQ service if not required
Stop-Service -Name MSMQ -Force
Set-Service -Name MSMQ -StartupType Disabled

# PowerShell: Block MSMQ port using Windows Firewall
New-NetFirewallRule -DisplayName "Block MSMQ Inbound" -Direction Inbound -Protocol TCP -LocalPort 1801 -Action Block