ABB Busch-Welcome 2 Wire Door Opener Actuator

ABB Busch-Welcome 2 Wire Door Opener Actuator contains an authentication bypass vulnerability (CVE-2025-7705) due to compatibility mode being enabled by default. The vulnerability affects all versions of Switch Actuator 4 DU and Switch actuator door/light 4 DU models. An attacker exploiting this vulnerability could gain unauthorized physical access to buildings where the product is installed. The vulnerability is caused by active debug code (CWE-489) and has a CVSS v3.1 score of 6.8 (Medium). ABB has provided mitigation steps involving toggling the mode switch and performing a power reset to recalibrate the system. The vulnerability affects commercial facilities worldwide.