Overview
CVE-2025-13751 describes a local denial-of-service (DoS) vulnerability affecting the interactive service agent in OpenVPN versions 2.5.0 through 2.7_rc2 running on Windows. An authenticated local user can exploit this vulnerability to connect to the service and trigger an error, ultimately leading to a denial of service.
Technical Details
The vulnerability exists within the OpenVPN interactive service agent on Windows. A local, authenticated user can connect to this service and manipulate it in a way that triggers an unhandled exception or error condition. This error effectively crashes the service agent, leading to a local denial-of-service. The specific mechanism by which this is achieved isn’t detailed in the initial advisories, but further investigation of the affected code versions would be needed to pinpoint the precise exploit trigger.
CVSS Analysis
Currently, the CVE record indicates that both the severity and CVSS score are marked as N/A (Not Available). This suggests the vulnerability’s impact assessment is still in progress or that the standard scoring methods may not adequately reflect its characteristics. While a local DoS might seem less critical than remote code execution, it’s important to remember the potential for privilege escalation when combined with other vulnerabilities.
Possible Impact
The most immediate impact of this vulnerability is a denial-of-service for the OpenVPN client on the affected Windows system. This can disrupt VPN connectivity, preventing users from accessing protected networks or resources. While the vulnerability requires local access and authentication, it could be exploited by malicious software already present on the system or by an attacker who has already compromised a user account. A successful attack will cause the OpenVPN service to terminate unexpectedly. This could be particularly problematic in environments where OpenVPN is relied upon for critical infrastructure access or data security.
Mitigation and Patch Steps
The recommended mitigation is to upgrade to a patched version of OpenVPN that addresses this vulnerability. Check the OpenVPN community website for the latest stable release. Based on the CVE description, versions prior to 2.5.0 and later than 2.7_rc2 are not affected.
- Upgrade OpenVPN: Download and install the latest stable version of OpenVPN from the official website.
- Monitor Systems: Keep an eye on systems running OpenVPN for unexpected crashes or service disruptions.
- Review Access Controls: Ensure that only authorized users have access to systems running OpenVPN to minimize the risk of exploitation by malicious insiders.
