A vulnerability has been identified in SIMATIC MV540 H (All versions < V3.3), SIMATIC MV540 S (All versions < V3.3), SIMATIC MV550 H (All versions < V3.3), SIMATIC MV550 S (All versions < V3.3), SIMATIC MV560 U (All versions < V3.3), SIMATIC MV560 X (All versions < V3.3). The web session management of affected devices does not invalidate session ids in certain logout scenarios. This could allow an authenticated remote attacker to hijack other users' sessions.