Denial of Service Vulnerability in OpenVPN Server Mode by OpenVPN

CVE-2025-2704

What is CVE-2025-2704?

CVE-2025-2704 is a denial of service vulnerability found in the server mode of OpenVPN, a widely used open-source software that enables secure point-to-point or site-to-site connections in routed or bridged configurations. This vulnerability affects versions 2.6.1 through 2.6.13 when utilizing the TLS-crypt-v2 feature, allowing remote attackers to disrupt service by corrupting and replaying packets during the initial handshake process. Such disruptions can prevent legitimate users from establishing secure connections, potentially halting critical business operations and damaging the organization's reputation for reliable service.

Technical Details

This vulnerability manifests during the early stages of the TLS handshake. Attackers can exploit the flaw by sending manipulated network packets that lead to corruption and replay scenarios. Specifically, the affected versions of OpenVPN do not adequately safeguard against these malicious packets, enabling denial-of-service conditions. The vulnerability is particularly concerning due to the fundamental role OpenVPN serves in maintaining secure communication channels between clients and servers.

Potential impact of CVE-2025-2704

1. Service Disruption: Organizations relying on OpenVPN for secure communications may face significant downtime, hindering operations and affecting productivity as users are unable to connect to the network.

2. Reputation Damage: Consistent service interruptions can lead to loss of customer trust and damage the organization's reputation, particularly if the uptime of their services is critical to business success.

3. Increased Recovery Costs: Addressing denial-of-service incidents often involves not only patching the software but also potentially investing in additional security measures, monitoring tools, and support to prevent future occurrences, which can lead to increased operational costs.

News Articles

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CVE-2025-2704

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