CVE-2025-54093 Overview
CVE-2025-54093 is a time-of-check time-of-use (TOCTOU) race condition in the Windows TCP/IP networking stack. An authorized local attacker can exploit the race window between a security check and the subsequent use of the checked resource to elevate privileges. Microsoft classifies the issue as an elevation of privilege vulnerability affecting supported Windows client and server releases, from Windows 10 1507 through Windows Server 2025. The weakness is tracked as CWE-367. Successful exploitation grants attacker code execution at a higher privilege context on the local system.
Critical Impact
A low-privileged local user who wins the race can escalate to elevated privileges, compromising confidentiality, integrity, and availability of the affected Windows host.
Affected Products
- Microsoft Windows 10 (1507, 1607, 1809, 21H2, 22H2)
- Microsoft Windows 11 (22H2, 23H2, 24H2)
- Microsoft Windows Server 2008, 2012, 2016, 2019, 2022, 2022 23H2, and 2025
Discovery Timeline
- 2025-09-09 - CVE-2025-54093 published to NVD
- 2026-06-17 - Last updated in NVD database
Technical Details for CVE-2025-54093
Vulnerability Analysis
The vulnerability resides in the Windows TCP/IP driver stack, which handles socket state, network buffers, and privileged kernel objects. A race condition occurs when the driver validates a property of an object or buffer, then later operates on that same resource under the assumption the check remains valid. An attacker running a concurrent thread can modify the resource between the check and the use. The subsequent operation then executes against attacker-controlled state within a privileged code path. This allows local privilege escalation into the kernel context. The attack requires a low-privileged local account and precise timing, which explains the high attack complexity metric.
Root Cause
The root cause is a classic TOCTOU flaw [CWE-367]. The affected TCP/IP code path performs a non-atomic sequence of validate-then-use on a shared resource without proper synchronization. Because the resource is reachable from user mode, an attacker can mutate it during the race window and bypass the safety guarantees the check was intended to provide.
Attack Vector
Exploitation requires local access with a valid user account. The attacker runs two or more threads that simultaneously issue socket or IOCTL operations targeting the vulnerable TCP/IP code path while mutating the shared object referenced by the driver. Winning the race causes the kernel to act on unvalidated state, yielding privilege escalation. No user interaction is required. Refer to the Microsoft CVE-2025-54093 Advisory for vendor-specific technical details.
Detection Methods for CVE-2025-54093
Indicators of Compromise
- Unexpected SYSTEM-level processes spawned from a standard user session shortly after intensive socket or IOCTL activity.
- New service installations, scheduled tasks, or credential dumping tools appearing after a low-privileged logon.
- Kernel crashes or tcpip.sys bug checks preceding suspicious process creation.
Detection Strategies
- Monitor Windows Security and Sysmon logs for process token elevation events where the parent process runs under a non-privileged user.
- Correlate high-frequency socket, DeviceIoControl, or Winsock API calls with subsequent creation of privileged processes.
- Apply behavioral EDR rules that flag user-mode code repeatedly racing the same kernel object handle.
Monitoring Recommendations
- Enable kernel-mode auditing and Windows Defender Exploit Guard logging on servers and workstations.
- Ingest endpoint telemetry into a SIEM or data lake and alert on local privilege-escalation patterns following TCP/IP driver anomalies.
- Baseline normal Winsock activity per user and alert on multi-threaded IOCTL bursts against \Device\Tcp or \Device\Afd.
How to Mitigate CVE-2025-54093
Immediate Actions Required
- Apply the Microsoft security update referenced in the Microsoft CVE-2025-54093 Advisory to all affected Windows client and server systems.
- Prioritize patching multi-user hosts, jump servers, and terminal servers where untrusted local accounts execute code.
- Audit local accounts and remove unnecessary interactive logon rights to reduce the attack surface for local exploitation.
Patch Information
Microsoft has released security updates addressing CVE-2025-54093 through the standard monthly update cycle. Consult the Microsoft CVE-2025-54093 Advisory for the specific KB article corresponding to each affected Windows build.
Workarounds
- No official workaround is published by Microsoft; installing the security update is the supported remediation.
- Restrict local logon and interactive access to trusted administrators until patches are deployed.
- Enforce application allowlisting to block unsigned or unknown binaries that could stage the race exploit.
Disclaimer: This content was generated using AI. While we strive for accuracy, please verify critical information with official sources.
