VIVOTEK IP Camera devices with firmware before 0x20x allow a denial of service via a crafted HTTP header.
https://www.vivotek.com/cybersecurity
https://euvd.enisa.europa.eu/vulnerability/EUVD-2019-5646
http://download.vivotek.com/downloadfile/support/cyber-security/vvtk-sa-2019-002-v1.pdf