The Horde Web Application Framework is a general-purpose web application framework written in PHP, providing classes for handling preferences, compression, browser detection, connection tracking, MIME, and more.
Michael Marek discovered that the Horde Web Application Framework performs insufficient input sanitizing.
An attacker could exploit these vulnerabilities to execute arbitrary scripts running in the context of the victim's browser.
There is no known workaround at this time.
All horde users should upgrade to the latest version:
# emerge --sync
# emerge --ask --oneshot --verbose ">=www-apps/horde-3.1.1-r1"