Updating MariaDB to v10.3.26 or 10.2.35 has been reported to generate errors with transferring accounts via the Transfer Tool or with backup restorations. This update also has been known to cause issues with sites with PHP versions older than 7.3 and cPanel UI issues with the MySQL Database interface reporting MySQL as offline.
These other two issues can be read about here, respectively:
After MariaDB update, PHP website has database connection error, 500 error, or white page: MySQL query error: Malformed communication packet
Updating MariaDB v10.2.35 or v10.3.26 causes MySQL Databases interface to show MySQL as offline.
Transfers or restores will show errors similar to below:
The "Mysql" restore module failed because of an error: Invalid grant string: SET DEFAULT ROLE 0 FOR 'testuser'@'10.1.1.3'
We've opened an internal case for our development team to investigate this further. For reference, the case number is CPANEL-34745. Follow this article to receive an email notification when a solution is published in the product.
As of 2020-11-06, our development team has released an autofixer to address this issue. It will be run automatically the next time the nightly maintenance runs. If you are experiencing this problem now, though, you may run the following autofixer script as root:
Note: If running the autorepair script above does not resolve your issue, please attempt restarting the SQL service.
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
Then run upcp to have the MariaDB packages updated: