CVE-2025-59507 Overview
CVE-2025-59507 is a race condition vulnerability in the Windows Speech component. The flaw stems from concurrent execution using a shared resource with improper synchronization [CWE-362]. An authenticated local attacker who wins the race can elevate privileges on the affected system. Microsoft addressed the issue through a security update published on November 11, 2025. The vulnerability affects a broad range of Windows client and server versions, including Windows 10, Windows 11, and Windows Server releases from 2016 through 2025.
Critical Impact
Successful exploitation grants an authorized local attacker elevated privileges, resulting in full compromise of confidentiality, integrity, and availability on the affected host.
Affected Products
- Microsoft Windows 10 (1607, 1809, 21H2, 22H2)
- Microsoft Windows 11 (23H2, 24H2, 25H2)
- Microsoft Windows Server 2016, 2019, 2022, 2022 23H2, and 2025
Discovery Timeline
- 2025-11-11 - CVE-2025-59507 published to the National Vulnerability Database (NVD)
- 2026-06-17 - Last updated in NVD database
Technical Details for CVE-2025-59507
Vulnerability Analysis
The defect resides in the Windows Speech subsystem, which exposes services accessible to local users. Two or more threads access a shared resource without correct synchronization primitives. A local attacker can trigger the race window by invoking Speech operations in parallel with a competing operation that modifies the same resource. Winning the race allows the attacker's code to run in the context of a higher-privileged process, resulting in local privilege escalation.
Root Cause
The root cause is classified as [CWE-362], concurrent execution using shared resource with improper synchronization. Missing or insufficient locking around a shared object allows a time-of-check to time-of-use style discrepancy. An attacker-controlled thread can alter the state of the resource between validation and use by the privileged component.
Attack Vector
Exploitation requires local access with low-privilege authenticated user rights and no user interaction. Attack complexity is high because the attacker must reliably win a timing-dependent race. In practice, this often means repeated attempts, thread priority manipulation, and CPU affinity tuning to widen the race window. Successful exploitation yields code execution in a privileged context on the target host. Refer to the Microsoft CVE-2025-59507 Advisory for vendor-specific details.
Detection Methods for CVE-2025-59507
Indicators of Compromise
- Unexpected child processes spawned by Windows Speech-related services or sapisvr.exe running with elevated tokens.
- Abnormal thread creation patterns targeting Speech-related DLLs from low-integrity user contexts.
- New scheduled tasks, services, or registry persistence entries created shortly after Speech component activity.
Detection Strategies
- Hunt for processes launched by Speech-related components that inherit SYSTEM or elevated tokens without a legitimate parent process lineage.
- Correlate rapid, repeated invocations of Speech APIs from a single user session with subsequent privilege changes.
- Monitor for anomalous handle duplication and impersonation events (Event ID 4624 with elevation, 4672) following Speech process activity.
Monitoring Recommendations
- Enable Windows Defender Application Control and Sysmon logging for process creation, thread injection, and handle events on endpoints and servers.
- Baseline expected behavior of Speech-related binaries and alert on deviations, including unusual DLL loads or command lines.
- Forward endpoint telemetry to a centralized SIEM or data lake for cross-host correlation of race-condition exploitation attempts.
How to Mitigate CVE-2025-59507
Immediate Actions Required
- Apply the Microsoft November 2025 security updates that address CVE-2025-59507 to all affected Windows client and server systems.
- Prioritize patch deployment on multi-user systems such as Remote Desktop Session Hosts and Virtual Desktop Infrastructure, where local attackers are most likely to be present.
- Audit local accounts and remove unnecessary interactive logon rights to reduce the pool of users who can attempt exploitation.
Patch Information
Microsoft released a security update for CVE-2025-59507 on November 11, 2025. Consult the Microsoft CVE-2025-59507 Advisory for the specific KB article and cumulative update aligned to each affected Windows build. Verify installation using wmic qfe list or the Update History interface after deployment.
Workarounds
- Disable or restrict access to Windows Speech features on systems where the functionality is not required, using Group Policy or service configuration.
- Restrict local logon rights on servers to trusted administrators to minimize the exposure window until patches are applied.
- Enforce the principle of least privilege and application allowlisting to limit an attacker's ability to stage exploitation binaries locally.
Disclaimer: This content was generated using AI. While we strive for accuracy, please verify critical information with official sources.
