CVE-2025-13751 in OpenVPN
Summary
by MITRE • 12/03/2025
Interactive service agent in OpenVPN version 2.5.0 through 2.6.16 and 2.7_alpha1 through 2.7_rc2 on Windows allows a local authenticated user to connect to the service and trigger an error causing a local denial of service.
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Analysis
by VulDB Data Team • 02/04/2026
The vulnerability identified as CVE-2025-13751 affects the interactive service agent component within OpenVPN versions ranging from 2.5.0 through 2.6.16 and 2.7_alpha1 through 2.7_rc2 on Windows operating systems. This issue represents a local privilege escalation vulnerability that allows authenticated users to exploit a flaw in the service agent's error handling mechanism. The vulnerability specifically targets the Windows implementation of OpenVPN's interactive service functionality, which is designed to provide a graphical user interface for managing VPN connections and service operations. The affected service agent operates with elevated privileges, making this vulnerability particularly concerning for system security.
The technical flaw manifests when a local authenticated user establishes a connection to the OpenVPN interactive service and triggers an error condition within the service agent's processing logic. This error condition causes the service agent to crash or become unresponsive, resulting in a local denial of service scenario. The vulnerability stems from inadequate error handling within the service agent code, where specific error conditions are not properly managed or recovered from, leading to service termination. According to CWE classification, this vulnerability maps to CWE-248, which describes an "Uncaught Exception" scenario where an exception or error condition is not properly handled by the application. The flaw exists in the service agent's input validation and error recovery mechanisms, specifically within the Windows service implementation that handles user interactions and connection management.
The operational impact of CVE-2025-13751 extends beyond simple service disruption as it affects the core functionality of OpenVPN's Windows implementation. When exploited, the vulnerability can cause the OpenVPN service to become unavailable, preventing legitimate users from establishing VPN connections while the service remains unresponsive. This denial of service condition can persist until the service is manually restarted or the system is rebooted, potentially disrupting business operations and network connectivity for users who rely on VPN services. The vulnerability affects systems where OpenVPN is installed with the interactive service enabled, which is typically configured to provide user-friendly management capabilities but introduces additional attack surface. From an ATT&CK perspective, this vulnerability aligns with techniques involving service execution and privilege escalation, specifically T1035 for service execution and T1068 for local privilege escalation, as it allows a local user to cause service disruption through authenticated access.
Mitigation strategies for CVE-2025-13751 should focus on immediate patching of affected OpenVPN installations to versions that address the service agent error handling flaw. Organizations should ensure all Windows systems running affected OpenVPN versions receive updates from the vendor as soon as patches become available. System administrators should also consider implementing additional monitoring for service availability and error conditions related to OpenVPN services, particularly in environments where multiple users may have local access to systems with the VPN client installed. The vulnerability can be partially mitigated by disabling the interactive service component if graphical management is not required, though this may limit administrative capabilities. Security teams should monitor for exploitation attempts through unusual service restart patterns or error logs related to OpenVPN service agent failures. Additionally, implementing least privilege principles for OpenVPN service accounts and restricting local access to systems running the VPN client can help reduce the attack surface for this vulnerability.