An Improper Limitation of a Pathname to a Restricted Directory (“Path Traversal”) in Fortinet FortiOS 6.0.0 to 6.0.4, 5.6.3 to 5.6.7 under SSL VPN web portal allows an unauthenticated attacker to download system files via special crafted HTTP resource requests.
Source: NIST
CVE-2018-13379 (fortios)