Affected devices contain a vulnerability that allows an unauthenticated attacker to trigger a denial of service condition. The vulnerability can be triggered if a large amount of DCP reset packets are sent to the device.
https://cert-portal.siemens.com/productcert/html/ssa-599968.html
https://us-cert.cisa.gov/ics/advisories/icsa-21-194-03
https://cert-portal.siemens.com/productcert/pdf/ssa-599968.pdf