Comment 0 for bug 1677924

Maor Schwartz discovered that a local attacker could watch for lightdm's
guest-account script to create a /tmp/guest-XXXXXX file and then quickly create
the lowercase representation of the guest user's home directory before lightdm
could. This allowed the attacker to have control of the guest user's home
directory and, subsequently, gain control of an arbitrary directory in the
filesystem which could lead to privilege escalation.