Windows RRAS Heap Overflow (CVE-2025-49676): Critical Vulnerability Enables Remote Code Execution

A critical heap-based buffer overflow in Windows Routing and Remote Access Service (RRAS) allows remote attackers to execute arbitrary code. Immediate patching is essential.
CVE Analysis

6 min read

ZeroPath Security Research

ZeroPath Security Research

2025-07-08

Windows RRAS Heap Overflow (CVE-2025-49676): Critical Vulnerability Enables Remote Code Execution

Windows RRAS Heap Overflow (CVE-2025-49676): Critical Vulnerability Enables Remote Code Execution

Introduction

A critical vulnerability in Windows Routing and Remote Access Service (RRAS) has emerged, posing significant risks to organizations relying on Windows Server infrastructure. CVE-2025-49676, a heap-based buffer overflow, can enable remote attackers to execute arbitrary code, potentially leading to full system compromise. Immediate action is required to mitigate this severe threat.

Technical Information

The vulnerability lies within the Windows RRAS, specifically in the improper handling of network packets. RRAS fails to perform adequate boundary checks when processing incoming data, resulting in a heap-based buffer overflow. Attackers exploit this flaw by sending specially crafted packets, causing memory corruption and allowing arbitrary code execution.

The attack vector is network-based, requiring no authentication. However, exploitation necessitates user interaction, such as initiating a connection to a malicious server. The heap overflow condition enables attackers to overwrite adjacent memory structures, potentially redirecting execution flow to attacker-controlled code.

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 the July 2025 Patch Tuesday. This update modifies the RRAS code to implement stricter bounds checking and input validation, effectively preventing the buffer overflow condition that could lead to remote code execution.

To apply this critical security fix, users should install the latest cumulative update for their respective Windows versions. For Windows 11 version 24H2, the update is identified as KB5062553. Detailed information and download links are available on Microsoft's official support page.

Administrators are strongly encouraged to deploy this update promptly to mitigate potential exploitation risks associated with this vulnerability.

Affected Systems and Versions

  • Windows 11 version 24H2 (update KB5062553 required)
  • All supported Windows Server versions utilizing RRAS are potentially vulnerable if unpatched.

Vendor Security History

Microsoft regularly addresses vulnerabilities through its monthly Patch Tuesday updates. Historically, Microsoft has faced similar memory safety vulnerabilities, particularly in legacy services like RRAS. Despite these challenges, Microsoft maintains a robust security response framework, exemplified by proactive vulnerability management practices and timely security updates.

References

Source: This report was created using AI

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