Bug #105016 create user with max_user_connections ,it save as Unexpected data
Submitted: 23 Sep 2021 9:03 Modified: 23 Sep 2021 10:57
Reporter: d f Email Updates:
Status: Verified Impact on me:
Category:MySQL Server: Options Severity:S3 (Non-critical)
Version:8.0.25, 8.0.26, 5.7.35 OS:Linux
Assigned to: CPU Architecture:Any

[23 Sep 2021 9:03] d f
Specify a large value of max_user_connections   when creating a user, and store a random number in the system table

How to repeat:
 create  user test4 with max_user_connections 4294967297;
Query OK, 0 rows affected (0.00 sec)

mysql> select * from mysql.user where User = "test4"\G
*************************** 1. row ***************************
                    Host: %
                    User: test4
             Select_priv: N
             Insert_priv: N
             Update_priv: N
             Delete_priv: N
             Create_priv: N
               Drop_priv: N
             Reload_priv: N
           Shutdown_priv: N
            Process_priv: N
               File_priv: N
              Grant_priv: N
         References_priv: N
              Index_priv: N
              Alter_priv: N
            Show_db_priv: N
              Super_priv: N
   Create_tmp_table_priv: N
        Lock_tables_priv: N
            Execute_priv: N
         Repl_slave_priv: N
        Repl_client_priv: N
        Create_view_priv: N
          Show_view_priv: N
     Create_routine_priv: N
      Alter_routine_priv: N
        Create_user_priv: N
              Event_priv: N
            Trigger_priv: N
  Create_tablespace_priv: N
              ssl_cipher: NULL
             x509_issuer: NULL
            x509_subject: NULL
           max_questions: 0
             max_updates: 0
         max_connections: 0
    max_user_connections: 1
                  plugin: caching_sha2_password
        password_expired: N
   password_last_changed: 2021-09-23 17:15:11
       password_lifetime: NULL
          account_locked: N
        Create_role_priv: N
          Drop_role_priv: N
  Password_reuse_history: NULL
     Password_reuse_time: NULL
Password_require_current: NULL
         User_attributes: NULL

Suggested fix:
When the specified size exceeds the maximum value, an error is reported or set to the maximum value and an alarm is reported.
[23 Sep 2021 10:57] MySQL Verification Team

Thank you for the report and feedback.