The remote host is running SquirrelMail, a web-based mail server.
There are several flaws in all versions less than 1.4.3 and development versions 1.5.0 and 1.5.1 which allow for local root access and remote Cross-Site-Scripting (XSS) attacks.
***** Nessus has determined the vulnerability exists on the target ***** simply by looking at the version number of Squirrelmail ***** installed there.
Solution : Upgrade to SquirrelMail 1.4.3 or greater.