The File Manager (gollem) module 3.0.11 in Horde Groupware 5.2.21 allows remote attackers to bypass Horde authentication for file downloads via a crafted fn parameter that corresponds to the exact filename.
IMP 2.2 and earlier allows attackers to read and delete arbitrary files by modifying the attachment_name hidden form variable, which causes IMP to send the file to the attacker as an attachment.
Horde IMP 4.3.6 and earlier does not request that the web browser avoid DNS prefetching of domain names contained in e-mail messages, which makes it easier for remote attackers to determine the network location of the webmail user by logging DNS requests.
Horde Application Framework 3.0.9 allows remote attackers to read arbitrary files via a null character in the url parameter in services/go.php, which bypasses a sanity check.
Horde IMP 2.2.7 allows remote attackers to obtain the full web root pathname via an HTTP request for (1) poppassd.php3, (2) login.php3?reason=chpass2, (3) spelling.php3, and (4) ldap.search.php3?ldap_serv=nonsense which leaks the information in error messages.