Netsweeper before 4.0.11 and 4.1.0 before 4.1.5 contains a reflected cross-site scripting vulnerability in webadmin/reporter/view_server_log.php that allows remote attackers to execute arbitrary JavaScript by injecting malicious code through the log request parameter, which is reflected into the HTML response without output encoding. Attackers can craft a malicious URL and induce a user to request it, resulting in arbitrary JavaScript execution within the victim's browser session against the Netsweeper web administration interface. Exploitation evidence was first observed by the Shadowserver Foundation on 2023-10-19.