# CVE-2026-84256 - Windows CreateProcess() command line quoting bypass via cmd.exe metacharacters

OpenVPN 2.x on Windows does not correctly quote command lines passed to `CreateProcess()` for characters that are special to `cmd.exe`. In combination with a validation script and a rogue CA, this could be used to make OpenVPN misbehave.

OpenVPN version 2.1_rc10 through 2.6.22 and 2.7_alpha1 through 2.7.6 are affected. This is fixed in version 2.7.7.

CVE Record: [CVE-2026-84256](https://www.cve.org/CVERecord?id=CVE-2026-84256)

Github:
* [OpenVPN/openvpn-private-issues#159](https://github.com/OpenVPN/openvpn-private-issues/issues/159)

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

Reported-By: Clouditera Security