The application suffers from a privilege escalation vulnerability. An attacker logged in as guest can escalate his privileges by poisoning the cookie to become administrator.
Exploitability
AV:NAC:LAT:NPR:LUI:NVulnerable System
VC:HVI:HVA:HSubsequent System
SC:NSI:NSA:N8.7/CVSS:4.0/AV:N/AC:L/AT:N/PR:L/UI:N/VC:H/VI:H/VA:H/SC:N/SI:N/SA:NOther