Moxa’s Ethernet switch EDS-508A Series, running firmware version 3.11 and earlier, is vulnerable to an authentication bypass because of flaws in its authorization mechanism. Although both client-side and back-end server verification are involved in the process, attackers can exploit weaknesses in its implementation. These vulnerabilities may enable brute-force attacks to guess valid credentials or MD5 collision attacks to forge authentication hashes, potentially compromising the security of the device.