This emergency update addresses CVE-2021-44228, a critical vulnerability found in the Log4j library that allows for remote code execution. The plugin uses the Log4j library to forward server logs to Telnet clients. Since Log4j is automatically included in compiled versions of this plugin, any servers running BukkitTelnet v4.6 (which don't have this update) are vulnerable.
If you have this plugin on your server, update it immediately to this version to stay secure.