CVE 2017-5180
Firejail before 0.9.44.4 and 0.9.38.x LTS before 0.9.38.8 LTS does not consider the .Xauthority case during its attempt to prevent accessing user files with an euid of zero, which allows local users to conduct sandbox-escape attacks via vectors involving a symlink and the --private option.
See the
CVE page on Mitre.org
for more details.