Bug report: abortion in sql/set_var.cc:0

I used my fuzzing tool to test Mariadb , and found a bug that can result in an abortion.

Mariadb installation：
1) cd mariadb-10.5.9
2) mkdir build; cd build
3) cmake -DWITH_ASAN=ON -DWITH_ASAN_SCOPE=ON -DWITH_DEBUG=ON ../
4) make -j8 && sudo make install

How to Repeat:
export ASAN_OPTIONS=detect_leaks=0
/usr/local/mysql/bin/mysqld_safe &
/usr/local/mysql/bin/mysql -uroot -p123456(your password)
MariaDB> drop database if exists test_db;
MariaDB> create database test_db;
MariaDB> source fuzz.sql;

I have simplified the content of fuzz.sql, and I hope fuzz.sql can help you reproduce the bug and fix it. In addition, I attach the abortion report (which has its stack trace).