OpenVPN 2.7.6 -- Released 5 August 2026

The OpenVPN community project team is proud to release OpenVPN 2.7.6. This is a bugfix release fixing several security issues.

For details see Changes.rst

Security fixes:

• openvpnserv (windows): better scrutinize command line passed in from the control socket to openvpn. This would lead to circumventing admin restrictions on allowed openvpn config directories (but never to "read files the user has no permissions for") (CVE-2026-63649)

  Bug found by 章鱼哥 (www.aipyaipy.com)

• dco: make key state desync recoverable

  This was reported as a "with suitable timing, a key-update de-sync between OpenVPN and the kernel could trigger an ASSERT()", and was initially handled as security report. It turned out to be not exploitable, but the state machine was not very robust and so the opportunity was used to improve the code.

  Bug found by 章鱼哥 (www.aipyaipy.com)

• make --x509-username-field work with mbedTLS.

  In very particular setups, together with a CA creating matching certificates, this could lead to unintentionally permitting a certificate that should not have. This is why this was considered a (low-prio) security bug and a CVE ID was assigned (CVE-2026-63650)

  Bug found by 章鱼哥 (www.aipyaipy.com)

User-visible Changes:

• if --dev is not specified, default to --dev tun - so for the tun case, this option can now be left out of the openvpn config.

• --ping and --keepalive settings are now limited to 24 hours maximum - the primary reason for that is to avoid lots of extra code in the DCO kernel to handle arbitrarily large values without overflowing 32 bit integers. 24h is considered much higher than any reasonable use.

• The TCP_NODELAY socket flag is now "always on". The --tcp-nodelay option is kept, because setting it on a p2mp server also enables pushing of socket-flags TCP_NODELAY to clients, which might not have this code change yet.

• Remove --providers from --help output on mbedTLS builds.

Bugfixes:

• refuse incoming HARD RESET packets with a sequence ID != 0 (this is basically making an OpenVPN server ignore and log a "should never happen" client-side misbehaviour, which could lead to TLS handshake establishment failures in p2p TLS setups)

• correctly calculate packet id size if epoch packet format is in use - this was off by 4, for connections openvpn 2.7+ to openvpn 2.7+, exceeding "mssfix mtu" headroom by those 4 bytes (Github: OpenVPN/openvpn#1074)

• correct minimum packet length check for 802.1q tagged packets (Github: OpenVPN/openvpn#1044).

  This was also reported (twice) as a security bug, as technically OpenVPN with --client-nat would read and write up to 4 bytes "after the end of the packet" - but due to the OpenVPN packet buffer layouts, which are always full-frame-sized this is fully safe and has no adverse consequences.

Windows MSI changes since 2.7.5-I001:

• Update included dco-win driver to v2.8.4
  • fix control channel stall (Github: ovpn-dco-win/issues/137)

For Community-maintained packages for Linux distributions see OpenVPN Software Repositories.

OpenVPN 2.6.22 -- Released 5 August 2026

The OpenVPN community project team is proud to release OpenVPN 2.6.22. This is a bugfix release fixing several security issues.

For details see Changes.rst

Security fixes:

• openvpnserv (windows): better scrutinize command line passed in from the control socket to openvpn. This would lead to circumventing admin restrictions on allowed openvpn config directories (but never to "read files the user has no permissions for") (CVE-2026-63649)

  Bug found by 章鱼哥 (www.aipyaipy.com)

• dco: make key state desync recoverable

  This was reported as a "with suitable timing, a key-update de-sync between OpenVPN and the kernel could trigger an ASSERT()", and was initially handled as security report. It turned out to be not exploitable, but the state machine was not very robust and so the opportunity was used to improve the code.

  Bug found by 章鱼哥 (www.aipyaipy.com)

Bugfixes:

• refuse incoming HARD RESET packets with a sequence ID != 0 (this is basically making an OpenVPN server ignore and log a "should never happen" client-side misbehaviour, which could lead to TLS handshake establishment failures in p2p TLS setups)

• correct minimum packet length check for 802.1q tagged packets (Github: OpenVPN/openvpn#1044).

  This was also reported (twice) as a security bug, as technically OpenVPN with --client-nat would read and write up to 4 bytes "after the end of the packet" - but due to the OpenVPN packet buffer layouts, which are always full-frame-sized this is fully safe and has no adverse consequences.

For Community-maintained packages for Linux distributions see OpenVPN Software Repositories.

Full Release History