Hirschmann OS2, RSP, and RSPE devices before HiOS 08.3.00 allow a denial of service. An unauthenticated, adjacent attacker can cause an infinite loop on one of the HSR ring ports of the device. This effectively breaks the redundancy of the HSR ring. If the attacker can perform the same attack on a second device, the ring is broken into two parts (thus disrupting communication between devices in the different parts).