A vulnerability has been identified in SIMATIC CP 1626 (All versions), SIMATIC ET 200SP Open Controller CPU 1515SP PC (incl. SIPLUS variants) (All versions), SIMATIC ET 200SP Open Controller CPU 1515SP PC2 (incl. SIPLUS variants) (All versions <= 20.8), SIMATIC ET200SP (incl. SIPLUS variants) Open Controller CPU 1515SP PC (All versions), SIMATIC ET200SP (incl. SIPLUS variants) Open Controller CPU 1515SP PC2 (All versions), SIMATIC HMI Panel (incl. SIPLUS variants) (All versions), SIMATIC NET PC Software (All versions), SIMATIC S7 PLCSIM Advanced (All versions <= V3.0), SIMATIC S7-1200 CPU family (incl. SIPLUS variants) (All versions <= V4.4), SIMATIC S7-1500 CPU family (incl. related ET200 CPUs and SIPLUS variants), excluding CPU 1518 MFP (and related SIPLUS variant) (All versions <= V2.8.1), SIMATIC S7-1500 CPU family (incl. related ET200 CPUs and SIPLUS variants), excluding CPU 1518-4 PN/DP and CPU 1518 MFP (and related SIPLUS variant) (All versions <= V2.8.1), SIMATIC S7-1500 Software Controller (All versions <= V20.8), SIMATIC STEP 7 (TIA Portal) (All versions < V16), SIMATIC WinCC (TIA Portal) (All versions < V16), SIMATIC WinCC OA (All versions <= 3.15), SIMATIC WinCC Runtime Advanced (All versions), SIMATIC WinCC Runtime Professional (All versions), TIM 1531 IRC (incl. SIPLUS variant) (All versions). An attacker in a Man-in-the-Middle position could potentially modify network traffic exchanged on port 102/tcp to PLCs of the SIMATIC S7-1200, SIMATIC S7-1500 and SIMATIC SoftwareController CPU families, due to certain properties in the calculation used for integrity protection. In order to exploit the vulnerability, an attacker must be able to perform a Man-in-the-Middle attack. The vulnerability could impact the integrity of the communication. No public exploitation of the vulnerability was known at the time of advisory publication.