The remote host has a web browser installed that is vulnerable to multiple attack vectors.
Versions of Mozilla Firefox 1.5.x prior to 188.8.131.52 are affected by various security issues, several of which are critical as they can be easily exploited to execute arbitrary shell code on the remote host. The version of Firefox is vulnerable to multiple denial of service attacks, overflows, information disclosure, privilege escalation, and other issues. An attacker exploiting these flaws would need to be able to convince a user to browse to a malicious URI.
Upgrade to version 184.108.40.206 or higher.