functions/imap_general.php in SquirrelMail before 1.4.21 does not properly handle 8-bit characters in passwords, which allows remote attackers to cause a denial of service (disk consumption) by making many IMAP login attempts with different usernames, leading to the creation of many preferences files.
Multiple cross-site request forgery (CSRF) vulnerabilities in SquirrelMail 1.4.19 and earlier, and NaSMail before 1.7, allow remote attackers to hijack the authentication of unspecified victims via features such as send message and change preferences, related to (1) functions/mailbox_display.php, (2) src/addrbook_search_html.php, (3) src/addressbook.php, (4) src/compose.php, (5) src/folders.php, (6) src/folders_create.php, (7) src/folders_delete.php, (8) src/folders_rename_do.php, (9) src/folders_rename_getname.php, (10) src/folders_subscribe.php, (11) src/move_messages.php, (12) src/options.php, (13) src/options_highlight.php, (14) src/options_identities.php, (15) src/options_order.php, (16) src/search.php, and (17) src/vcard.php.
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.