scponlyc in scponly 4.1 and earlier, when the operating system supports LD_PRELOAD mechanisms, allows local users to execute arbitrary code with root privileges by creating a chroot directory in their home directory, hard linking to a system setuid application, and using a modified LD_PRELOAD to modify expected function calls in the setuid application.
Argument injection vulnerability in scponlyc in scponly 4.1 and earlier, when both scp and rsync compatibility are enabled, allows local users to execute arbitrary applications via "getopt" style argument specifications, which are not filtered.