CVE-2026-40215 is a race condition vulnerability in OpenVPN versions 2.6.0 through 2.6.19 and 2.7_alpha1 through 2.7.1. The issue arises from a use-after-free condition triggered during TLS session promotion, which can be exploited by remote attackers to cause a denial of service (server crash) or leak heap memory. The vulnerability is identified as CWE-125 (Out-of-bounds Read). The CVSS 3.1 score is 7.4, reflecting a moderate severity with network attack vector, high attack complexity, no privileges required, no user interaction, and high impact on confidentiality and availability.

Successful exploitation can lead to a server crash causing denial of service or the leakage of heap memory, potentially exposing sensitive information. There is no indication of integrity impact. The vulnerability can be triggered remotely without authentication or user interaction, but requires high attack complexity.

Patch status is not yet confirmed — check the vendor advisory for current remediation guidance. No official fix or patch links are provided in the available data. Users should monitor official OpenVPN advisories for updates and apply patches once available.