The two PDF files shared as proof of the attack can be considered weapons: [...] SHA-1 colliding files are currently breaking SVN repositories. Subversion servers use SHA-1 for deduplication and repositories become corrupted when two colliding files are committed to the repository. This has been discovered in WebKit's Subversion repository and

Matt Green: In crypto we have the idea that hash function collisions should be really hard to find, even if they're 'useless'. [...] [A real-world collision attack] is the equivalent of finding out that your scalpel wasn't sterilized properly. It may not verifiably have germs on it, but the whole instrument