A vulnerability has been identified in SIMATIC MV540 H (All versions < V3.3.4), SIMATIC MV540 S (All versions < V3.3.4), SIMATIC MV550 H (All versions < V3.3.4), SIMATIC MV550 S (All versions < V3.3.4), SIMATIC MV560 U (All versions < V3.3.4), SIMATIC MV560 X (All versions < V3.3.4). The result synchronization server of the affected products contains a vulnerability that may lead to a denial of service condition. An attacker may cause a denial of service situation of all socket-based communication of the affected products if the result server is enabled.
https://cert-portal.siemens.com/productcert/pdf/ssa-561322.pdf