An unauthenticated and remote adversary can consume all of the device's CPU due to crafted HTTP requests sent to SMA100 /fileshare/sonicfiles/sonicfiles resulting in a loop with unreachable exit condition. This vulnerability affected SMA 200, 210, 400, 410 and 500v appliances.
https://psirt.global.sonicwall.com/vuln-detail/SNWLID-2021-0026