CVE 2006-6142
Multiple cross-site scripting (XSS) vulnerabilities in SquirrelMail 1.4.0 through 1.4.9 allow remote attackers to inject arbitrary web script or HTML via the (1) mailto parameter in (a) webmail.php, the (2) session and (3) delete_draft parameters in (b) compose.php, and (4) unspecified vectors involving "a shortcoming in the magicHTML filter."
See the
CVE page on Mitre.org
for more details.