The PROFINET (PNIO) stack, when integrated with the Interniche IP stack, improperly handles internal resources for TCP segments where the minimum TCP-Header length is less than defined. This could allow an attacker to create a denial of service condition for TCP services on affected devices by sending specially crafted TCP segments.

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.