Windows RRAS Under Siege: Unpacking CVE-2025-49668's Heap-Based Buffer Overflow

A critical heap-based buffer overflow in Windows RRAS (CVE-2025-49668) allows remote attackers to execute arbitrary code. Immediate patching is essential.
CVE Analysis

5 min read

ZeroPath Security Research

ZeroPath Security Research

2025-07-08

Windows RRAS Under Siege: Unpacking CVE-2025-49668's Heap-Based Buffer Overflow

Introduction

Windows Routing and Remote Access Service (RRAS), a critical component for VPN and remote access solutions, faces a severe threat from CVE-2025-49668—a heap-based buffer overflow vulnerability. With a CVSS score of 8.8, this flaw allows remote attackers to execute arbitrary code, posing significant risks to enterprise environments.

Technical Information

The vulnerability stems from improper memory handling within RRAS during network packet processing. Specifically, the flaw involves inadequate bounds checking in the packet-parsing logic, allowing attackers to craft malicious packets that trigger a heap-based buffer overflow (CWE-122). This overflow corrupts memory structures, enabling attackers to execute arbitrary code remotely with elevated privileges.

Attack vectors include sending specially crafted network packets directly to vulnerable RRAS instances. The vulnerability requires no authentication, has low complexity, and can be exploited remotely, significantly increasing the risk of widespread exploitation.

Patch Information

Microsoft has addressed the heap-based buffer overflow vulnerability in the Windows Routing and Remote Access Service (RRAS) by releasing a security update as part of their July 2025 Patch Tuesday. This update modifies how RRAS handles memory operations to prevent unauthorized code execution over a network. Administrators are advised to apply this update promptly to mitigate potential exploitation risks.

Affected Systems and Versions

  • Windows Server 2012
  • Windows Server 2016
  • Windows Server 2019
  • Windows Server 2022
  • Windows 10
  • Windows 11

All configurations running RRAS without the July 2025 security update are vulnerable.

Vendor Security History

Microsoft has faced similar memory-safety vulnerabilities in RRAS, notably CVE-2025-26668 and CVE-2025-49670. The recurrence of these issues underscores ongoing challenges in securing legacy networking components. Microsoft's timely patching and detailed advisories reflect an improved security posture, though systemic memory-safety issues remain a concern.

References

Source: This report was created using AI

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