MD5 heads for retirement
Vlastimil Klíma has alledgedly managed to create a very efficient tool for finding MD5 collisions. A slow (1 GHz) home PC was able to find collisions on average in 4 h 11 min. The attack works for any selected IV, and is a real threat to any persistent MD5 signatures.
Arjen Lenstra, Xiaoyun Wang and Benne de Weger have announced a pair of valid X.509 certificates with an identical signature. Essentially this means that any certificate chains that have MD5 signatures in them are suspicious.