Git through 2.14.2 mishandles layers of tree objects, which allows remote attackers to cause a denial of service (memory consumption) via a crafted repository, aka a Git bomb. This can also have an impact of disk consumption; however, an affected process typically would not survive its attempt to build the data structure in memory before writing to disk.
https://usn.ubuntu.com/3829-1/
http://lists.opensuse.org/opensuse-security-announce/2020-05/msg00003.html