When multiple devices share resources and one of them is to be passed through to a guest, security of the entire system and of respective guests individually cannot really be guaranteed without knowing internals of any of the involved guests. Therefore such a configuration cannot really be security-supported, yet making that explicit was so far missing.
Resources the sharing of which is known to be problematic include, but are not limited to
Exploitability
AV:LAC:HPR:HUI:NScope
S:CImpact
C:HI:HA:H7.5/CVSS:3.1/AV:L/AC:H/PR:H/UI:N/S:C/C:H/I:H/A:H