From zdnet.com
Attacks on the SHA-1 hashing algorithm just got a lot more dangerous last week with the discovery of the first-ever “chosen-prefix collision attack,” a more practical version of the SHA-1 collision attack first carried out by Google two years ago.
What this means is that SHA-1 collision attacks can now be carried out with custom inputs, and they’re not just accidental mishaps anymore, allowing attackers to target certain files to duplicate and forge.