This module exploits a vulnerability in Linux. The ovl_setattr function in fs/overlayfs/inode.c in the Linux kernel through 4.3.3 attempts to merge distinct setattr operations, which allows local users to bypass intended access restrictions and modify the attributes of arbitrary overlay files via a crafted application.
The 'sosreport' program, part of the ABRT bug reporting system used in Red Hat Enterprise Linux, does not handle symbolic links correctly when writing core dumps of ABRT programs to the ABRT dump directory (/var/tmp/abrt). This can be leveraged by local unprivileged attackers to gain root privileges on vulnerable systems.