Windows RRAS Under Siege: Analyzing the Critical CVE-2025-49663 Heap-Based Buffer Overflow

Introduction

Microsoft's Windows Routing and Remote Access Service (RRAS), a crucial component for VPN and network routing, faces a critical security threat. CVE-2025-49663, a heap-based buffer overflow vulnerability, allows unauthenticated attackers to execute arbitrary code remotely, potentially compromising entire systems. With a CVSS score of 8.8, this vulnerability demands immediate attention from security teams.

Technical Information

CVE-2025-49663 is rooted in insufficient boundary checks within the heap memory operations of RRAS when processing network packets. Attackers exploit this vulnerability by sending specially crafted packets that exceed the allocated buffer space, causing a heap-based buffer overflow. This overflow corrupts adjacent memory regions, enabling attackers to hijack the control flow and execute malicious shellcode embedded within the packets.

The attack vector is network-based and requires no authentication, significantly increasing the risk. Exploitation can occur over multiple RRAS-supported protocols, complicating detection and prevention efforts.

Patch Information

Microsoft has addressed this vulnerability with cumulative updates KB5028185 for Windows 11 version 22H2 and KB5028182 for version 21H2, released on July 11, 2023. These updates enhance OS security and specifically address critical vulnerabilities, including CVE-2025-49663. Users are strongly advised to install these updates promptly to mitigate potential security risks. Updates are available through Windows Update, Microsoft Update, and the Microsoft Update Catalog.

Affected Systems and Versions

The vulnerability specifically impacts:

Windows Server 2012 R2 through 2025
Windows 10 versions 21H2 to 24H2
Windows 11 versions 21H2 and 22H2
Windows Server Core installations

Systems running RRAS in default configurations are vulnerable and require immediate patching.

Vendor Security History

Microsoft has faced repeated vulnerabilities in RRAS, with July 2025 alone seeing 14 disclosed vulnerabilities. This pattern highlights persistent weaknesses in RRAS's codebase, despite Microsoft's mature security response and regular patching cycles.

References

Source: This report was created using AI

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A critical heap-based buffer overflow in Windows RRAS (CVE-2025-49663) allows unauthenticated attackers remote code execution—here's what you need to know.