DotDeb.org has released updated MySQL 4.0.23 and 4.1.8 packages for Debian GNU/Linux 3.0
A security alert has been published on MySQL 4.0 and 4.1 :Here the apt source:
http://www.debian.org/security/2005/dsa-647
I just uploaded new packages that fix it. Please apt-get upgrade as soon as possible.
deb http://packages.dotdeb.org ./