CVE-2025-49666: Windows Kernel Heap Overflow Opens Door to Remote Code Execution

Introduction

A newly disclosed heap-based buffer overflow vulnerability in the Windows Kernel, identified as CVE-2025-49666, poses a significant risk by enabling authorized attackers to execute arbitrary code remotely. This flaw specifically targets the Windows Setup and Boot Event Collection (SBEC) service, a critical component responsible for logging boot-time events on Windows Server systems.

Technical Information

The vulnerability stems from improper memory handling within the SBEC service. The Windows Kernel fails to adequately validate buffer boundaries when processing incoming network event data. Attackers can exploit this oversight by sending specially crafted oversized packets, causing a heap-based buffer overflow. This overflow corrupts adjacent memory structures, potentially allowing attackers to overwrite critical kernel pointers and inject malicious code.

Attackers require authenticated network access to exploit this vulnerability, making it particularly concerning for environments where user credentials might be compromised. The exploitation process involves sending malicious packets to the SBEC service (default UDP port 50000), resulting in unauthorized remote code execution with SYSTEM-level privileges.

Affected Systems and Versions

Windows Server 2019
Windows Server 2022
Windows 10 Enterprise (configured as SBEC collectors)
Windows 11 Enterprise (configured as SBEC collectors)

Systems without SBEC enabled or with restricted network access to the SBEC service are not vulnerable.

Patch Information

Microsoft has addressed the heap-based buffer overflow vulnerability in the Windows Kernel by releasing a security update as part of their July 2025 Patch Tuesday. This update modifies how the Windows Kernel handles memory operations to prevent unauthorized code execution over a network. By applying this patch, the system's memory management is enhanced, mitigating the risk associated with this vulnerability. Users are strongly encouraged to install this update promptly to ensure their systems are protected.

Vendor Security History

Microsoft consistently addresses vulnerabilities through monthly security updates, known as Patch Tuesday. Despite their proactive approach, kernel-level vulnerabilities like CVE-2025-49666 highlight ongoing challenges in secure memory management. Microsoft's prompt response to this vulnerability demonstrates their commitment to security, although similar kernel heap overflow vulnerabilities have been periodically identified and patched in the past.

Threat Intelligence

Currently, there is no evidence of active exploitation of CVE-2025-49666. However, given the vulnerability's potential for high-impact exploitation and low complexity, it is likely that threat actors, including ransomware groups and APTs, could quickly adopt this exploit. Organizations should prioritize patch deployment and maintain heightened vigilance.

References

Source: This report was created using AI

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A critical heap-based buffer overflow in the Windows Kernel (CVE-2025-49666) allows authorized attackers to execute arbitrary code remotely, highlighting urgent patching needs.

CVE Analysis