Cacti 1.1.38 allows authenticated users with User Management permissions to inject arbitrary web script or HTML in the "new_username" field during creation of a new user via "Copy" method at user_admin.php.
Exploitability
AV:NAC:LPR:LUI:RScope
S:CImpact
C:LI:LA:N5.4/CVSS:3.1/AV:N/AC:L/PR:L/UI:R/S:C/C:L/I:L/A:NInjection