Hash collisions

The acknowledged weakness in SHA1 means that it is possible to find a pair of texts, given control over both texts, that hash to the same value much faster than the expected 2^80 steps.

But most attacks on a VCS involve taking a known text, and finding another text that hashes to the same value; often this is just solving the pre-image problem, which is much harder. There is no suggestion in the open literature that the collision weakness of SHA1 is matched by a comparable pre-image one.