Debian 9973 Published by has released MySQL 5.5.25 packages for Debian

The packages of MySQL 5.5.25 are now available for Debian 6.0 Squeeze on both amd64 and i386 architectures. They fixes some InnoDB- and replication-related issues. As usual, please read carefully the full Changelog before upgrading.
  MySQL 5.5.25 for Debian