Horde Groupware Webmail Edition through 5.2.22 allows a reflection injection attack through which an attacker can instantiate a driver class. This then leads to arbitrary deserialization of PHP objects.
An XSS issue was discovered in Horde Groupware Webmail Edition through 5.2.22 (where the Horde_Text_Filter library before 2.3.7 is used). The attacker can send a plain text e-mail message, with JavaScript encoded as a link or email that is mishandled by preProcess in Text2html.php, because bespoke use of \x00\x00\x00 and \x01\x01\x01 interferes with XSS defenses.
The image view functionality in Horde Groupware Webmail Edition before 5.2.22 is affected by a stored Cross-Site Scripting (XSS) vulnerability via an SVG image upload containing a JavaScript payload. An attacker can obtain access to a victim's webmail account by making them visit a malicious URL.
Horde Trean, as used in Horde Groupware Webmail Edition through 5.2.22 and other products, allows CSRF, as demonstrated by the treanBookmarkTags parameter to the trean/ URI on a webmail server. NOTE: treanBookmarkTags could, for example, be a stored XSS payload.
Horde Groupware Webmail Edition through 5.2.22 allows XSS via an admin/user.php?form=update_f&user_name= or admin/user.php?form=remove_f&user_name= or admin/config/diff.php?app= URI.
In Horde_Crypt before 2.7.6, as used in Horde Groupware Webmail Edition through 5.2.17, OS Command Injection can occur if the attacker is an authenticated Horde Webmail user, has PGP features enabled in their preferences, and attempts to encrypt an email addressed to a maliciously crafted email address.
In Horde_Crypt before 2.7.6, as used in Horde Groupware Webmail Edition 5.x through 5.2.17, OS Command Injection can occur if the user has PGP features enabled in the user's preferences, and has enabled the "Should PGP signed messages be automatically verified when viewed?" preference. To exploit this vulnerability, an attacker can send a PGP signed email (that is maliciously crafted) to the Horde user, who then must either view or preview it.