# CVE-2026-78043 - Windows openvpnserv config path validation bypass using '/' separator

OpenVPN 2.x on Windows allows local users to start openvpn.exe with a config file that is administratively not allowed, because the Windows APIs used for path validation do not treat '/' as a path separator while the file open APIs do, so a '/' in the config path can be used to circumvent the config path validation in `openvpnserv`.

OpenVPN version 2.7_alpha1 through 2.7.6 are affected. This is fixed in version 2.7.7.

CVE Record: [CVE-2026-78043](https://www.cve.org/CVERecord?id=CVE-2026-78043)

Github:
* [OpenVPN/openvpn-private-issues#162](https://github.com/OpenVPN/openvpn-private-issues/issues/162)

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

Reported-By: BreachX Zero Day Labs (using Typhon AI Mil v2)