openvpn -- 2.6.0...2.6.6 --fragment option division by zero crash, and TLS data leak

The OpenVPN community project team reports:

CVE-2023-46849 OpenVPN versions between 2.6.0 and 2.6.6 incorrectly restore “–fragment” configuration in some circumstances, leading to a division by zero when “–fragment” is used. On platforms where division by zero is fatal, this will cause an OpenVPN crash.

Reported by Niccolo Belli and WIPocket (Github #400, #417).

CVE-2023-46850 OpenVPN versions between 2.6.0 and 2.6.6 incorrectly use a send buffer after it has been free()d in some circumstances, causing some free()d memory to be sent to the peer. All configurations using TLS (e.g. not using --secret) are affected by this issue. (found while tracking down CVE-2023-46849 / Github #400, #417)