Symfony is a PHP framework for web and console applications and a set of reusable PHP components. From 7.1.0 until 7.4.12 and 8.0.12, Cas2Handler builds the CAS service parameter from Request::getSchemeAndHttpHost(), which reflects an attacker-controlled Host header when framework.trusted_hosts is not configured; an attacker controlling another application registered with the same CAS server can replay a victim ticket against the Symfony application and authenticate as the victim. This issue is fixed in versions 7.4.12 and 8.0.12.
Exploitability
AV:NAC:LAT:PPR:NUI:PVulnerable System
VC:HVI:HVA:NSubsequent System
SC:NSI:NSA:N7.6/CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:P/VC:H/VI:H/VA:N/SC:N/SI:N/SA:NOther