Executive brief
OpenVPN is a widely used software for creating secure private network connections. A vulnerability has been identified where an authenticated user can send specially crafted data packets to cause the VPN service to crash or leak sensitive memory information. This could lead to a disruption of secure remote access for all users or the potential exposure of internal system data.
Technical details
A use-after-free (CWE-416) and out-of-bounds read (CWE-125) vulnerability exists in OpenVPN's handling of TLS sessions. The flaw is triggered during TLS session promotion or expiry when processing crafted packets from a remote authenticated peer. An attacker with valid credentials can exploit this to cause a denial of service (application crash) or potentially leak memory contents. The vulnerability affects versions 2.6.0 through 2.6.20 and 2.7_alpha1 through 2.7.4. Patches are available in OpenVPN versions 2.6.21 and 2.7.5.
Affected products
- OpenVPN Inc. OpenVPN 2.6.0 through 2.6.20, 2.7_alpha1 through 2.7.4
Timeline
- 2026-07-01: patched: OpenVPN 2.6.21 and 2.7.5 released to address the issue.
- 2026-07-30: disclosed: CVE-2026-12996 published.