From the WordPress Blog:
WordPress 2.3.2 is an urgent security release that fixes a bug that can be used to expose your draft posts. 2.3.2 also suppresses some error messages that can give away information about your database table structure and limits and stops some information leaks in the XML-RPC and APP implementations. Get 2.3.2 now to protect your blog from these disclosures.
Stop! Update time! Ta dadada tada tada. Update time!
Update: Here’s Peter Westwood’s “WordPress 2.3.2 in detail“, with backlinks to addressed Trac tickets.