Executive brief
OpenVPN is a widely used software for creating secure private network connections. A flaw in how it handles specific security keys allows an attacker to repeatedly send specially crafted data packets that consume the server's memory. This can eventually crash the service, preventing legitimate users from connecting to the VPN and disrupting remote access for the organization.
Technical details
A memory leak vulnerability (CWE-401) exists in OpenVPN's tls-crypt-v2 client key extraction component. The flaw is triggered during the processing of crafted packets, where the application fails to release memory after its effective lifetime. A remote attacker with low privileges can exploit this over the network by flooding the service with these packets, leading to memory exhaustion and a Denial of Service (DoS) condition. The issue affects versions 2.5.0 through 2.6.20 and 2.7_alpha1 through 2.7.4, and has been addressed in versions 2.6.21 and 2.7.5.
Affected products
- OpenVPN OpenVPN 2.5.0 through 2.6.20, 2.7_alpha1 through 2.7.4
Timeline
- 2026-07-01: patched: OpenVPN versions 2.6.21 and 2.7.5 released to address the issue.
- 2026-07-30: advisory: CVE-2026-12932 published.