A vulnerability in the login dialog box of SIMATIC WinCC could allow a local attacker to cause a denial of service condition in the runtime of the SCADA system.
Siemens has released new versions for several affected products and recommends to update to the latest versions. Siemens is preparing further fix versions and recommends specific countermeasures for products where fixes are not, or not yet available.

https://cert-portal.siemens.com/productcert/html/ssa-730482.html