First Chosen-Prefix Collision on SHA-1 and Application to the PGP Web of Trust

Quoting the abstract:

>> Therefore, the same attacks that have been practical on MD5 since 2009 are now practical on SHA-1. In particular, chosen-prefix collisions can break signature schemes and handshake security in secure channel protocols (TLS, SSH). We strongly advise to remove SHA-1 from those type of applications as soon as possible. <<