CVE-1999-1559

CVE-1999-1559 describes a vulnerability in Xylan OmniSwitch devices running versions prior to 3.2.6. An unauthenticated remote attacker can bypass the login prompt by sending a CTRL-D character, which then locks out legitimate users as the switch only supports a single session. This vulnerability is rated as Medium severity (CVSS 5.0), indicating a network-based attack with low complexity, requiring no authentication, and resulting in a partial denial of service. There is no evidence of active exploitation, public exploit code (Metasploit, Nuclei, ExploitDB), or significant community discussion surrounding this older vulnerability.