Security fixes

• CVE-2024-5594: control channel: refuse control channel messages with nonprintable characters in them. Security scope: a malicious openvpn peer can send garbage to openvpn log, or cause high CPU load. (Reynir Björnsson)

  (Backport of the security fix in 2.6.11 and the fix for the bugfix in 2.6.12)

Full Changelog: https://github.com/OpenVPN/openvpn/compare/v2.5.10...v2.5.11