Multiple cross-site scripting (XSS) vulnerabilities in SquirrelMail before 1.4.18 and NaSMail before 1.7 allow remote attackers to inject arbitrary web script or HTML via vectors involving (1) certain encrypted strings in e-mail headers, related to contrib/decrypt_headers.php; (2) PHP_SELF; and (3) the query string (aka QUERY_STRING).

Cross-site scripting (XSS) vulnerability in SquirrelMail before 1.4.17 allows remote attackers to inject arbitrary web script or HTML via a crafted hyperlink in an HTML part of an e-mail message.

SquirrelMail 1.4.11 and 1.4.12, as distributed on sourceforge.net before 20071213, has been externally modified to create a Trojan Horse that introduces a PHP remote file inclusion vulnerability, which allows remote attackers to execute arbitrary code.