Fedora has issued an update for horde. This fixes multiple vulnerabilities, which can be exploited by malicious users to compromise a vulnerable system and by malicious people to disclose potentially sensitive information, conduct cross-site scripting, and script insertion attacks.

For more information:
SA31842
SA33521
SA33695
SA36665
SA37709

Solution
Apply updated packages via the yum utility ("yum update horde").
Original Advisory
FEDORA-2010-5483:
https://admin.fedoraproject.org/updates/horde-3.3.6-1.fc11

FEDORA-2010-5520:
https://admin.fedoraproject.org/updates/horde-3.3.6-1.fc12

Other references
Further details available to Secunia VIM customers

Deep Links
Links available to Secunia VIM customers