scponly 4.6 and earlier allows remote authenticated users to bypass intended restrictions and execute code by invoking dangerous subcommands including (1) unison, (2) rsync, (3) svn, and (4) svnserve, as originally demonstrated by creating a Subversion (SVN) repository with malicious hooks, then using svn to trigger execution of those hooks.

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.

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.

The unison command in scponly before 4.0 does not properly restrict programs that can be run, which could allow remote authenticated users to bypass intended access restrictions and execute arbitrary programs via the (1) -rshcmd or (2) -sshcmd flags.

scponly does not properly verify the path when finding the (1) scp or (2) sftp-server programs, which could allow remote authenticated users to bypass access controls by uploading malicious programs and modifying the PATH variable in $HOME/.ssh/environment to locate those programs.