CVE-2026-62747: Windows 10 1607 Privilege Escalation Flaw

CVE-2026-62747 Overview

CVE-2026-62747 is a heap-based buffer overflow [CWE-122] in the Windows Device Association Service. An authorized local attacker can exploit the flaw to elevate privileges on affected Windows client and server systems. Microsoft published the advisory on 2026-08-11 and rated the issue with a CVSS 3.1 base score of 7.8. The vulnerability affects a broad set of supported Windows releases, including Windows 10, Windows 11, and Windows Server editions from 2016 through 2025. Successful exploitation grants high impact to confidentiality, integrity, and availability without user interaction.

Critical Impact
A local, low-privileged attacker can corrupt heap memory in the Device Association Service to execute code in an elevated context, resulting in full system compromise.

Affected Products

Microsoft Windows 10 (1607, 1809, 21H2, 22H2) across x86, x64, and ARM64 builds
Microsoft Windows 11 (23H2, 24H2, 25H2, 26H1) across x64 and ARM64 builds
Microsoft Windows Server 2016, 2019, 2022, and 2025

Discovery Timeline

2026-08-11 - CVE-2026-62747 published to the National Vulnerability Database
2026-08-11 - Microsoft releases security update for CVE-2026-62747
2026-08-13 - Last updated in NVD database

Technical Details for CVE-2026-62747

Vulnerability Analysis

The Windows Device Association Service (DeviceAssociationService) brokers pairing and connection state between Windows and external devices such as Bluetooth, Wi-Fi Direct, and companion peripherals. The service runs as a system component and processes requests originating from local user sessions through RPC and IPC channels. A heap-based buffer overflow [CWE-122] in this component allows an authenticated local user to corrupt heap memory during request processing.

Because the service executes in a privileged context, attacker-controlled memory writes can be leveraged to redirect execution flow or overwrite object metadata used by the service. Exploitation results in code execution at the service's privilege level, enabling privilege escalation from a standard user account to a higher-integrity context.

Root Cause

The root cause is insufficient bounds checking when the Device Association Service copies attacker-influenced data into a heap-allocated buffer. When the input length exceeds the allocated size, adjacent heap chunks and control structures are overwritten. This class of defect is tracked as [CWE-122: Heap-based Buffer Overflow].

Attack Vector

The attack vector is local and requires low-level privileges, but no user interaction. An attacker with the ability to execute code as a standard user sends crafted requests to the Device Association Service. The malformed request triggers the overflow inside the service process, allowing the attacker to influence execution and gain elevated privileges. This vulnerability is not remotely exploitable and is not currently listed on the CISA Known Exploited Vulnerabilities catalog. The EPSS score at publication is 0.318%.

No public proof-of-concept code is available at the time of writing. Refer to the Microsoft Security Update Guide for CVE-2026-62747 for vendor technical details.

Detection Methods for CVE-2026-62747

Indicators of Compromise

Unexpected crashes or restarts of the DeviceAssociationService process recorded in the Windows Application or System event logs.
Windows Error Reporting (WER) dumps referencing heap corruption faults inside DeviceAssociationService.dll or the hosting svchost.exe instance.
New child processes spawned by the Device Association Service host that do not match a known baseline of legitimate device pairing activity.
Standard-user accounts suddenly performing actions requiring SYSTEM or administrative privileges shortly after Device Association Service activity.

Detection Strategies

Baseline the normal behavior of svchost.exe instances hosting the Device Association Service and alert on anomalous module loads, child processes, or token manipulation.
Monitor for process integrity level transitions where a medium-integrity user process is followed by SYSTEM-context activity linked to Device Association RPC calls.
Correlate crash telemetry with subsequent privileged operations to identify potential exploitation attempts against the service.

Monitoring Recommendations

Enable Windows audit policies for process creation (Event ID 4688) and token privilege use, and forward the logs to a centralized analytics platform.
Track patch compliance across Windows 10, Windows 11, and Windows Server fleets to confirm the August 2026 security update is applied.
Review RPC endpoint activity involving the Device Association Service for calls originating from unusual or newly created user accounts.

How to Mitigate CVE-2026-62747

Immediate Actions Required

Apply the Microsoft security update referenced in the MSRC advisory for CVE-2026-62747 to all affected Windows client and server systems.
Prioritize patching on multi-user systems such as Remote Desktop Session Hosts, Virtual Desktop Infrastructure, and shared workstations where local users are most likely to exist.
Audit local account membership and remove unnecessary interactive logon rights on servers to reduce the pool of accounts able to reach the vulnerable service.

Patch Information

Microsoft addressed CVE-2026-62747 in the August 2026 security update cycle. The patch corrects the bounds handling in the Device Association Service to prevent heap corruption from oversized input. Refer to the Microsoft Security Update Guide for CVE-2026-62747 for KB article numbers and per-product package identifiers.

Workarounds

No official vendor workaround is documented; installing the security update is the supported remediation path.
Where patching must be deferred, restrict local logon on affected systems to trusted administrators to limit exposure.
Consider disabling the Device Association Service on servers that do not require companion device pairing, after validating operational impact in a test environment.

bash

# Verify the Device Association Service state and confirm patch level on a Windows host
Get-Service -Name DeviceAssociationService
Get-HotFix | Sort-Object -Property InstalledOn -Descending | Select-Object -First 10