Affected: Siemens SIDOOR ATD430W, Siemens SIDOOR ATE530G COATED, Siemens SIDOOR ATE530S COATED, Siemens SIMATIC CFU DIQ, Siemens SIMATIC CFU PA, Siemens SIMATIC ET 200AL IM 157-1 PN, Siemens SIMATIC ET 200clean, CM 8x IO-Link, Siemens SIMATIC ET 200clean, DI 16x24VDC, Siemens SIMATIC ET 200clean, DIQ 16x24VDC/0,5A, Siemens SIMATIC ET 200eco PN, AI 8xRTD/TC, M12-L and 135 more

Affected products do not properly enforce TCP sequence number validation in specific scenarios but accept values within a broad range. This could allow an unauthenticated remote attacker e.g. to interfere with connection setup, potentially leading to a denial of service. The attack succeeds only if an attacker can inject IP packets with spoofed addresses at precisely timed moments, and it affects only TCP-based services.