# CVE-2026-84471 - Possible double-free in check_session_buf_not_used() lame duck handling

OpenVPN 2.x allows attackers to potentially cause a double-free of a TLS session buffer in the lame duck case, because the guard in `check_session_buf_not_used()` was incomplete. This extends the earlier fix for CVE-2026-13117.

OpenVPN version 2.6.0 through 2.6.22 and 2.7_alpha1 through 2.7.6 are affected. This is fixed in versions 2.6.23 and 2.7.7.

CVE Record: [CVE-2026-84471](https://www.cve.org/CVERecord?id=CVE-2026-84471)

Github:
* [OpenVPN/openvpn-private-issues#157](https://github.com/OpenVPN/openvpn-private-issues/issues/157)
* [OpenVPN/openvpn-private-issues#132](https://github.com/OpenVPN/openvpn-private-issues/issues/132)

Release notes:
* [openvpn-2.7.7](https://community.openvpn.net/ReleaseHistory#openvpn-277-released-3-september-2026)
* [openvpn-2.6.23](https://community.openvpn.net/ReleaseHistory#openvpn-2623-released-23-september-2026)

Reported-By: Andreas Gabriel Berbescu, and Haruki Oyama (Waseda University)