SQLSTATE[HY000]: General error: 1835 Malformed communication packet on LARAVEL

Question

Suddenly got

SQLSTATE[HY000]: General error: 1835 Malformed communication packet (SQL: select * from tb_users where (username =

Answer 1

The official fix is finanlly out and you can find the details on the link:
https://support.cpanel.net/hc/en-us/articles/360056772334/comments/360005577354

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To quickly fix it just connect via SSH and run

sudo /scripts/autorepair fix_mariadb_show_grants_roles

For users that have applied the previous workaround involving downgrading MariaDB. Be sure to unlock MariaDB to ensure it continues to receive the appropriate updates:

yum versionlock clear
/scripts/upcp

Answer 2

This sudden error message is caused by a MariaDB client upgrade, which appears to be incompatible with the PHP 7.2 version of php-mysqlnd; version 10.2.35 breaks it, but version 10.2.34 still works. With yum or dnf one can easily revert to the previous versions eg. with:

su
yum history
yum history undo 440

Temporary setting enabled=0 in /etc/yum.repo.d/mariadb.repo might also make sense.
Upgrading to PHP 7.3 might still be the better option (while available).