Firejail before 0.9.44.6 and 0.9.38.x LTS before 0.9.38.10 LTS does not comprehensively address dotfile cases 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. NOTE: this vulnerability exists because of an incomplete fix for CVE-2017-5180.
Gentoo Linux Security Advisory 201702-3 - Firejail is vulnerable to the escalation of privileges due to an incomplete fix for CVE-2017-5180. Versions less than 0.9.44.8 are affected.