Kentico Xperience before 13.0.178 has a specific set of allowed ContentUploader file extensions for unauthenticated uploads; however, because .zip is processed through TryZipProviderSafe, there is additional functionality to create files with other extensions. NOTE: this is a separate issue not necessarily related to SVG or XSS.
Exploitability
AV:NAC:LPR:NUI:NScope
S:CImpact
C:NI:LA:L7.2/CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:N/I:L/A:LOther