Describe CVE-2021-40368.
What is CVE-2021-40368?
A vulnerability has been identified in  SIMATIC S7-400 CPU 412-1 DP V7 (All versions),  SIMATIC S7-400 CPU 412-2 DP V7 (All versions),  SIMATIC S7-400 CPU 412-2 PN/DP V7 (All versions < V7.0.3),  SIMATIC S7-400 CPU 414-2 DP V7 (All versions),  SIMATIC S7-400 CPU 414-3 DP V7 (All versions),  SIMATIC S7-400 CPU 414-3 PN/DP V7 (All versions < V7.0.3),  SIMATIC S7-400 CPU 414F-3 PN/DP V7 (All versions < V7.0.3),  SIMATIC S7-400 CPU 416-2 DP V7 (All versions),  SIMATIC S7-400 CPU 416-3 DP V7 (All versions),  SIMATIC S7-400 CPU 416-3 PN/DP V7 (All versions < V7.0.3),  SIMATIC S7-400 CPU 416F-2 DP V7 (All versions),  SIMATIC S7-400 CPU 416F-3 PN/DP V7 (All versions < V7.0.3),  SIMATIC S7-400 CPU 417-4 DP V7 (All versions), SIMATIC S7-400 H V6 CPU family (incl. SIPLUS variants) (All versions < V6.0.10), SIMATIC S7-410 V10 CPU family (incl. SIPLUS variants) (All versions < V10.1), SIMATIC S7-410 V8 CPU family (incl. SIPLUS variants) (All versions < V8.2.3), SIPLUS S7-400 CPU 414-3 PN/DP V7 (All versions < V7.0.3), SIPLUS S7-400 CPU 416-3 PN/DP V7 (All versions < V7.0.3), SIPLUS S7-400 CPU 416-3 V7 (All versions), SIPLUS S7-400 CPU 417-4 V7 (All versions). Affected devices improperly handle specially crafted packets sent to port 102/tcp.

This could allow an attacker to create a Denial-of-Service condition. A restart is needed to restore normal operations..