The check_secret function in authenticate.c in rsync 3.1.0 and earlier allows remote attackers to cause a denial of service (infinite loop and CPU consumption) via a user name which does not exist in the secrets file.

rsync 3.x before 3.0.8, when certain recursion, deletion, and ownership options are used, allows remote rsync servers to cause a denial of service (heap memory corruption and application crash) or possibly execute arbitrary code via malformed data.