Phorum allows remote attackers to hijack sessions of other users by stealing and replaying the session hash in the phorumuriauth parameter, as demonstrated using profile.php. NOTE: the affected version was reported to be 4.3.7, but this may be erroneous.

Directory traversal vulnerability in pm.php in Phorum 5 allows remote authenticated users to include and execute arbitrary local files via directory traversal sequences in the GLOBALS[template] parameter, as demonstrated by injecting PHP sequences into a log file, which is then included by pm.php.

Multiple cross-site scripting (XSS) vulnerabilities in Phorum 5.0.17a and earlier allow remote attackers to inject arbitrary web script or HTML via (1) the username parameter to register.php or (2) a signature of a logged-in user in "My Control Center," which is not properly handled by control.php.

Cross-site scripting (XSS) vulnerability in Phorum before 5.2.15 allows remote attackers to inject arbitrary web script or HTML via an invalid email address.

Cross-site scripting (XSS) vulnerability in Phorum before 5.2.10 allows remote attackers to inject arbitrary web script or HTML via unspecified vectors.