I can confirm this regression on Debian 12 after upgrading:
mariadb-server 1:10.11.14-0+deb12u2
to
mariadb-server 1:10.11.18-0+deb12u1
My server configuration explicitly contains:
[mysqld]
bind-address = 0.0.0.0
port = 3307
MariaDB reads this configuration correctly:
$ mariadbd --print-defaults | tr ' ' '\n' | grep '^--port'
--port=3307
However, after the upgrade, the server was listening on port 3306:
$ ss -lntp | grep -E ':3306|:3307'
LISTEN 0 4096 *:3306
/:/users:(("mariadbd",pid=6193,fd=5),("systemd",pid=1,fd=52))
Disabling and masking mariadb.socket restored the configured behavior:
$ systemctl disable --now mariadb.socket
$ systemctl mask mariadb.socket
$ systemctl restart mariadb.service
Afterward, MariaDB correctly listened on the configured port:
$ netstat -lpn | grep 330
tcp 0 0 0.0.0.0:3307 0.0.0.0:* LISTEN 9290/mariadbd
This appears to be a security-sensitive stable-release regression
because a routine package upgrade can cause MariaDB to listen on a
different TCP port than the one explicitly configured by the administrator.
Please consider ensuring that existing installations retain their
previous listener configuration unless socket activation is explicitly
enabled by the administrator.
