Error
Error Code:
1873
MariaDB Error 1873: Unauthorized User Context Change
Description
This error indicates that an attempt to switch to a different MariaDB user within an existing connection was denied. This typically occurs when a client tries to use the `CHANGE USER` command but fails authentication or authorization checks, leading to the connection being terminated.
Error Message
Access denied trying to change to user '%s'@'%s' (using password: %s). Disconnecting.
Known Causes
3 known causesIncorrect Username or Host
The specified username or host for the target user does not exist or is incorrectly entered in MariaDB's grant tables.
Invalid Password
The password provided for the target user account is incorrect, preventing successful authentication during the user change.
Insufficient Privileges
The currently connected user lacks the necessary `CHANGE USER` privilege or other required grants to switch to the desired user account.
Solutions
3 solutions available1. Verify User Credentials and Host Permissions easy
Ensure the username, password, and originating host are correctly configured and allowed.
1
Identify the user and host attempting to connect. This information is usually available in the error message itself or in MariaDB's error logs. For example, if the error message shows '%s'@'%s', replace '%s' with the actual username and host.
Example: 'user'@'localhost'2
Connect to MariaDB as a user with sufficient privileges (e.g., root).
mysql -u root -p3
Check the existing user grants for the user and host combination. Look for any explicit `GRANT USAGE ON *.* TO 'user'@'host';` or specific database grants.
SHOW GRANTS FOR 'username'@'hostname';
-- Example: SHOW GRANTS FOR 'app_user'@'192.168.1.100';4
If the user or host combination is not properly granted, or if the password is incorrect, recreate the user with the correct password and host permissions. Ensure the password matches what the client is using.
-- If the user doesn't exist or needs a password reset:
CREATE USER 'username'@'hostname' IDENTIFIED BY 'new_password';
-- Example: CREATE USER 'app_user'@'localhost' IDENTIFIED BY 'StrongPassword123';
-- If the user exists but needs a password update:
ALTER USER 'username'@'hostname' IDENTIFIED BY 'new_password';
-- Example: ALTER USER 'app_user'@'localhost' IDENTIFIED BY 'StrongPassword123';
-- Grant necessary privileges (at least USAGE for login):
GRANT USAGE ON *.* TO 'username'@'hostname';
-- Example: GRANT USAGE ON *.* TO 'app_user'@'localhost';
-- Apply changes
FLUSH PRIVILEGES;5
Attempt to connect again from the client application or tool using the verified credentials and hostname.
N/A2. Review and Adjust `skip-name-resolve` Configuration medium
Ensure hostname resolution is correctly configured to prevent authentication issues.
1
Locate your MariaDB configuration file. Common locations include `/etc/my.cnf`, `/etc/mysql/my.cnf`, or `/etc/mysql/mariadb.conf.d/50-server.cnf`.
N/A2
Open the configuration file with a text editor. You'll likely need root privileges.
sudo nano /etc/my.cnf3
Look for the `skip-name-resolve` directive. This directive controls whether MariaDB resolves hostnames or uses IP addresses for authentication. If it's commented out or set to `0`, MariaDB attempts hostname resolution.
[mysqld]
# skip-name-resolve4
If `skip-name-resolve` is enabled (i.e., uncommented or set to `1`), MariaDB will use IP addresses for user authentication. If you are using hostnames in your `GRANT` statements (e.g., `'user'@'my_server.local'`) and `skip-name-resolve` is enabled, MariaDB might not be able to match the connecting IP address to the hostname, leading to this error. Consider disabling `skip-name-resolve` or ensuring your `GRANT` statements use IP addresses if `skip-name-resolve` is enabled.
[mysqld]
skip-name-resolve = 0 # Or comment out the line entirely5
If you made changes, save the configuration file and restart the MariaDB service.
sudo systemctl restart mariadb6
Test the connection again. If you disabled `skip-name-resolve`, ensure that reverse DNS lookups are working correctly on your network, or revert to using IP addresses in your `GRANT` statements.
N/A3. Granting `USAGE` Privilege for All Hosts medium
Broaden access to allow login from any host for a specific user.
1
Connect to your MariaDB server with administrative privileges.
mysql -u root -p2
Execute the following SQL command to grant the `USAGE` privilege to the user from any host (`%`). This allows the user to connect but doesn't grant access to any specific databases.
GRANT USAGE ON *.* TO 'username'@'%';
-- Example: GRANT USAGE ON *.* TO 'app_user'@'%';3
Apply the privilege changes.
FLUSH PRIVILEGES;4
Attempt to connect from the client. This solution is useful if the specific client IP address is dynamic or difficult to pin down, but it reduces security by allowing connections from anywhere.
N/A