CVE-2026-62792: Windows 10 1607 Buffer Overflow Flaw

CVE-2026-62792 Overview

CVE-2026-62792 is a stack-based buffer overflow [CWE-121] in the Windows TCP/IP network stack. An unauthenticated remote attacker can send crafted network traffic to a vulnerable host and execute arbitrary code in the context of the kernel networking components. Microsoft addressed the flaw through its August 2026 security update guide.

The vulnerability affects all currently supported Windows client and server releases, including Windows 10, Windows 11, and Windows Server 2012 through Windows Server 2025. No authentication or user interaction is required, though the attack complexity is rated high.

Critical Impact
Successful exploitation grants remote code execution with full confidentiality, integrity, and availability impact across the entire supported Windows fleet.

Affected Products

Microsoft Windows 10 (1607, 1809, 21H2, 22H2) across x86, x64, and ARM64
Microsoft Windows 11 (23H2, 24H2, 25H2, 26H1) across x64 and ARM64
Microsoft Windows Server 2012, 2012 R2, 2016, 2019, 2022, and 2025

Discovery Timeline

2026-08-11 - CVE-2026-62792 published to the National Vulnerability Database
2026-08-11 - Microsoft releases security update via msrc.microsoft.com
2026-08-13 - Last updated in NVD database

Technical Details for CVE-2026-62792

Vulnerability Analysis

The flaw resides in the Windows TCP/IP driver stack, which parses inbound Internet Protocol traffic before user-mode handlers are invoked. A stack-based buffer overflow occurs when the driver processes a specially crafted packet whose length or option field does not match the size of the fixed stack buffer used to hold parsed data.

Because TCP/IP parsing runs in kernel context, corrupting the stack allows an attacker to overwrite the saved return address or adjacent kernel structures. The attack vector is network-based and pre-authentication, but the vulnerability carries a high attack complexity rating, indicating that the attacker must win a race condition, spray the kernel pool, or precisely align packet contents to achieve reliable code execution.

Root Cause

The root cause is missing or incorrect bounds validation on an attacker-controlled length or option field before data is copied into a fixed-size stack buffer inside the TCP/IP driver. This maps to the classic CWE-121 pattern, in which the destination buffer size is smaller than the source data length.

Attack Vector

An attacker sends malformed IP packets to any interface where the vulnerable host accepts network traffic. Exposure increases sharply on hosts with public interfaces, edge servers, VPN concentrators, and domain controllers reachable from lower-trust segments. Successful exploitation yields kernel-level code execution, enabling installation of rootkits, credential theft, and lateral movement.

No public proof-of-concept or in-the-wild exploitation has been reported at time of publication. Refer to the Microsoft Security Update CVE-2026-62792 advisory for the authoritative technical description.

Detection Methods for CVE-2026-62792

Indicators of Compromise

Unexplained bugchecks or stop errors referencing tcpip.sys shortly after inbound network traffic bursts.
Kernel crash dumps containing corrupted return addresses on threads originating in TCP/IP receive paths.
Anomalous inbound IPv4 or IPv6 packets with malformed option headers or oversized length fields from untrusted sources.

Detection Strategies

Deploy network intrusion detection signatures that flag malformed IP option fields, fragmented packets with inconsistent length values, and unusual protocol combinations targeting Windows hosts.
Correlate Windows Event Log entries for system crashes (Event ID 1001) and driver failures with concurrent inbound traffic anomalies.
Enable kernel-mode telemetry to capture unexpected transitions in tcpip.sys and subsequent process creation from System (PID 4) contexts.

Monitoring Recommendations

Monitor edge and internal firewalls for spikes in dropped or malformed packets destined for Windows hosts.
Track patch compliance across all Windows 10, Windows 11, and Windows Server assets using authenticated vulnerability scanning.
Alert on new listening services or scheduled tasks created immediately after kernel-level events on internet-facing systems.

How to Mitigate CVE-2026-62792

Immediate Actions Required

Apply the August 2026 Microsoft security update referenced in the Microsoft Security Update CVE-2026-62792 advisory to all supported Windows systems.
Prioritize internet-facing hosts, domain controllers, and remote access gateways where the TCP/IP stack is directly exposed.
Confirm patch installation with authenticated scanning and asset inventory reconciliation.

Patch Information

Microsoft has released cumulative updates for all affected Windows client and server versions through the Microsoft Update Guide. Administrators should deploy the update via Windows Update, Windows Server Update Services (WSUS), Microsoft Endpoint Configuration Manager, or Intune. Server 2012 and 2012 R2 require Extended Security Updates.

Workarounds

Restrict inbound IPv4 and IPv6 traffic to trusted sources using host-based firewall rules where operationally feasible.
Disable unused network protocols and interfaces to reduce exposure of the TCP/IP driver to untrusted traffic.
Segment vulnerable Windows hosts from lower-trust networks until patches are fully deployed.

bash

# Example: block inbound traffic from untrusted subnets via Windows Firewall
New-NetFirewallRule -DisplayName "Block-Untrusted-Inbound-CVE-2026-62792" `
    -Direction Inbound `
    -Action Block `
    -RemoteAddress 0.0.0.0/0 `
    -Profile Any `
    -Enabled True