P5 FNIP-8x16A/FNIP-4xSH versions 1.0.20 and 1.0.11 suffer from a stored cross-site scripting vulnerability. Input passed to several GET/POST parameters is not properly sanitized before being returned to the user, allowing attackers to execute arbitrary HTML and script code in a user's browser session in the context of the affected site. This can be exploited by submitting crafted input to the label modification functionality, such as the 'lab4' parameter in config.html.