Critical Security Alert: CVE-2025-49672 Vulnerability in Windows RRAS

The Windows Routing and Remote Access Service (RRAS) has recently been identified as vulnerable to a critical security flaw, designated as CVE-2025-49672. This vulnerability is a heap-based buffer overflow that allows unauthorized attackers to execute arbitrary code over a network, posing significant risks to systems utilizing RRAS.
Understanding CVE-2025-49672
CVE-2025-49672 is a heap-based buffer overflow vulnerability within the Windows RRAS. Buffer overflow vulnerabilities occur when a program writes more data to a buffer than it can hold, leading to adjacent memory corruption. In this case, an attacker can exploit the overflow to execute arbitrary code remotely, potentially gaining control over the affected system.
Technical Details
The vulnerability resides in how RRAS handles certain network packets. By sending specially crafted packets, an attacker can trigger the buffer overflow, leading to remote code execution. The Common Vulnerability Scoring System (CVSS) has assigned this vulnerability a score of 8.8, indicating a high severity level. The CVSS vector string is CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H, which translates to:

• Attack Vector (AV): Network
• Attack Complexity (AC): Low
• Privileges Required (PR): Low
• User Interaction (UI): None
• Scope (S): Unchanged
• Confidentiality Impact (C): High
• Integrity Impact (I): High
• Availability Impact (A): High

This scoring indicates that the vulnerability is exploitable over a network with low complexity, requires low privileges, and does not necessitate user interaction. Successful exploitation can lead to significant impacts on confidentiality, integrity, and availability.
Affected Systems
All versions of Windows Server that include RRAS are potentially affected by this vulnerability. This includes, but may not be limited to:

• Windows Server 2016
• Windows Server 2019
• Windows Server 2022

Organizations utilizing RRAS for VPN services, network routing, or remote access should consider their systems at risk.
Exploitation and Impact
An attacker exploiting CVE-2025-49672 can achieve remote code execution, potentially leading to:

• System Compromise: Full control over the affected server.
• Data Exfiltration: Unauthorized access to sensitive information.
• Service Disruption: Denial of service conditions, rendering RRAS or dependent services unavailable.

The network-based nature of this vulnerability means that attackers can exploit it remotely, increasing the risk for internet-exposed systems.
Mitigation and Remediation
Microsoft has released security updates to address CVE-2025-49672. Administrators are strongly advised to:

• Apply Security Patches: Ensure that all affected systems are updated with the latest security patches provided by Microsoft.
• Restrict RRAS Exposure: Limit the exposure of RRAS to trusted networks and implement firewall rules to control access.
• Monitor Network Traffic: Implement monitoring to detect unusual or suspicious network activity targeting RRAS.
• Review Access Controls: Ensure that only authorized users have access to RRAS and related services.

Conclusion
CVE-2025-49672 represents a significant security risk to organizations utilizing Windows RRAS. Prompt application of security updates and adherence to best practices in network security are essential to mitigate the potential impacts of this vulnerability.

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Source: MSRC Security Update Guide - Microsoft Security Response Center