backintime (aka Back in Time) before 1.1.24 did improper escaping/quoting of file paths used as arguments to the 'notify-send' command, leading to some parts of file paths being executed as shell commands within an os.system call in qt4/plugins/notifyplugin.py. This could allow an attacker to craft an unreadable file with a specific name to run arbitrary shell commands.
https://security.gentoo.org/glsa/201801-06
https://github.com/bit-team/backintime/releases/tag/v1.1.24
https://github.com/bit-team/backintime/issues/834
https://github.com/bit-team/backintime/commit/cef81d0da93ff601252607df3db1a48f7f6f01b3