IceWarp Web Mail 5.5.1, as used by Merak Mail Server 8.3.0r and VisNetic Mail Server version 8.3.0 build 1, does not properly restrict acceptable values for the language parameter to mail/settings.html before it is stored in a database, which can allow remote authenticated users to include arbitrary PHP code via a URL in a modified langsettings parameter to mail/index.html.

dir/include.html in IceWarp Web Mail 5.5.1, as used by Merak Mail Server 8.3.0r and VisNetic Mail Server version 8.3.0 build 1, allows remote attackers to include arbitrary local files via a null byte (%00) in the lang parameter, possibly due to a directory traversal vulnerability.

mail/include.html in IceWarp Web Mail 5.5.1, as used by Merak Mail Server 8.3.0r and VisNetic Mail Server version 8.3.0 build 1, does not properly initialize the defaultlayout and layoutsettings variables when an unrecognized HTTPUSERAGENT string is provided, which allows remote attackers to access arbitrary files via a request with an unrecognized User Agent that also specifies the desired defaultlayout and layoutsettings parameters.

PHP remote file include vulnerability in IceWarp Web Mail 5.5.1, as used by Merak Mail Server 8.3.0r and VisNetic Mail Server version 8.3.0 build 1, when registerglobals is enabled, allows remote attackers to include arbitrary local and remote PHP files via a URL in the (1) langsettings and (2) language parameters in (a) accounts/inc/include.php and (b) admin/inc/include.php.