CVE-2025-62213 Overview
CVE-2025-62213 is a use-after-free vulnerability [CWE-416] in the Windows Ancillary Function Driver for WinSock (afd.sys). The flaw allows an authenticated local attacker to elevate privileges on affected Windows client and server systems. Microsoft disclosed the issue on November 11, 2025, as part of its coordinated security update cycle.
Successful exploitation grants the attacker SYSTEM-level privileges, providing full control over the compromised host. The vulnerability affects a wide range of supported Windows releases, from Windows 10 1607 through Windows 11 25H2 and Windows Server 2008 through Windows Server 2025.
Critical Impact
An authorized local attacker can achieve kernel-level privilege escalation on affected Windows systems, undermining endpoint integrity and enabling persistent post-compromise activity.
Affected Products
- Microsoft Windows 10 (versions 1607, 1809, 21H2, 22H2)
- Microsoft Windows 11 (versions 23H2, 24H2, 25H2)
- Microsoft Windows Server 2008, 2012, 2016, 2019, 2022, 2022 23H2, and 2025
Discovery Timeline
- 2025-11-11 - Microsoft publishes the CVE-2025-62213 advisory and CVE is published to NVD
- 2026-06-17 - Last updated in NVD database
Technical Details for CVE-2025-62213
Vulnerability Analysis
The Ancillary Function Driver for WinSock (afd.sys) is a kernel-mode driver that provides the underlying transport interface for user-mode WinSock applications. Because afd.sys executes in kernel context and is reachable from any local process, memory-safety bugs in the driver are a recurring source of local privilege escalation on Windows.
This issue is a use-after-free condition. The driver continues to reference an object after that object has been freed, allowing a local attacker to manipulate the reclaimed allocation and influence subsequent kernel operations. Successful exploitation yields code execution in kernel mode with SYSTEM privileges.
The attack surface requires local access and valid credentials. The CVSS vector indicates high attack complexity, meaning the attacker must win a race window or satisfy specific timing conditions to reliably trigger the free-then-reuse pattern.
Root Cause
The root cause is improper object lifetime management inside afd.sys [CWE-416]. A code path releases a kernel object without clearing or synchronizing all outstanding references. A concurrent or follow-on IOCTL request then dereferences the stale pointer, operating on attacker-controlled data placed in the reclaimed pool allocation.
Attack Vector
Exploitation requires the attacker to already have authenticated local access on the target, such as a standard user session, remote desktop foothold, or code execution obtained through phishing or another initial-access vector. The attacker issues a crafted sequence of WinSock-related IOCTLs to afd.sys to trigger the free of a target object, then races to reclaim the freed pool memory before the driver reuses the stale pointer.
By shaping the reclaimed allocation with a controlled kernel object, the attacker steers subsequent kernel writes or function pointer dereferences and elevates the calling process token to SYSTEM. Public technical details and a proof-of-concept are not available at the time of writing. Refer to the Microsoft CVE-2025-62213 advisory for vendor guidance.
Detection Methods for CVE-2025-62213
Indicators of Compromise
- Unexpected SYSTEM-level child processes spawned from standard user sessions, particularly shells, cmd.exe, or powershell.exe with anomalous parent chains
- Kernel bug checks or afd.sys crash dumps generated on hosts where exploit attempts fail
- Newly created services, scheduled tasks, or local administrator accounts following a suspicious low-privilege process burst
Detection Strategies
- Hunt for token elevation events where a process running as a standard user briefly opens handles to SYSTEM-owned processes such as lsass.exe or winlogon.exe
- Correlate high-volume WinSock IOCTL activity with subsequent privilege changes on the same host within a short time window
- Alert on process integrity level transitions from Medium to System in the absence of legitimate elevation events (UAC, service start, scheduled task)
Monitoring Recommendations
- Ingest Windows Security, Sysmon, and kernel telemetry into a centralized analytics platform to enable cross-source correlation of privilege escalation patterns
- Enable and monitor Microsoft-Windows-Kernel-General and driver crash telemetry for repeated afd.sys faults
- Track process ancestry and command-line arguments for standard users invoking uncommon system binaries after network-related activity
How to Mitigate CVE-2025-62213
Immediate Actions Required
- Apply the November 2025 Microsoft security updates addressing CVE-2025-62213 to all affected Windows client and server systems
- Prioritize patching multi-user systems, jump hosts, and terminal servers where local access by lower-privileged users is common
- Audit local account inventories and remove unnecessary interactive logon rights to reduce the pool of accounts that can trigger the flaw
Patch Information
Microsoft has published patches through the Microsoft Security Update Guide entry for CVE-2025-62213. Administrators should install the appropriate cumulative or monthly rollup for each affected Windows and Windows Server SKU listed in the advisory.
Workarounds
- No official vendor workaround is documented; installing the security update is the supported remediation
- Enforce least-privilege policies and restrict local logon rights on servers to limit exposure until patching completes
- Apply application allowlisting to block untrusted binaries from executing WinSock exploit code on high-value hosts
Disclaimer: This content was generated using AI. While we strive for accuracy, please verify critical information with official sources.
