A vulnerability has been identified in SCALANCE X300 (All versions < V4.0.0), SCALANCE X408 (All versions < V4.0.0), SCALANCE X414 (All versions). The web interface on port 443/tcp could allow an attacker to cause a Denial-of-Service condition by sending specially crafted packets to the web server. The device will automatically reboot, impacting network availability for other devices. An attacker must have network access to port 443/tcp to exploit the vulnerability. Neither valid credentials nor interaction by a legitimate user is required to exploit the vulnerability. There is no confidentiality or integrity impact, only availability is temporarily impacted. This vulnerability could be triggered by publicly available tools.
https://ics-cert.us-cert.gov/advisories/ICSA-18-254-05
https://cert-portal.siemens.com/productcert/pdf/ssa-447396.pdf