Hardlink before 0.1.2 has multiple integer overflows leading to heap-based buffer overflows because of the way string lengths concatenation is done in the calculation of the required memory space to be used. A remote attacker could provide a specially-crafted directory tree and trick the local user into consolidating it, leading to hardlink executable crash or potentially arbitrary code execution with user privileges.
https://security-tracker.debian.org/tracker/CVE-2011-3631
https://bugzilla.redhat.com/show_bug.cgi?id=CVE-2011-3631