L2J Server

I've some function wich checks insert data from HTML before SQL querry sending. But it works only for eng chars, such as latin but.. if I try to check cyrilic symbols or all symbols wich mysql supports, such as it requires in utf8mb4, is this my new regualr expression will be working, and is it will be safe for mysql queries? p.s. I said about utf8mb4 because want to try queries with other chars in future, chinese for example but I not sure that lineage client support it thereat korean сome down

You can take a look into in regex. It represents word characters. Maybe it matches cyrilic and others also.

I don't know wich chars in \w range, I want to use separate chars from chinese or korean lang and add support for cyrillic users.
I want to sure that regex is safe for querries.

If you use prepared statements it is safe. Prepared statements are there to protect you from SQL injections. It works by not embedding the user Input directly into the query string but give it as a seperate Parameter which can be sanitized then.