WebAccess in Zarafa before 7.1.10 and WebApp before 1.6 stores credentials in cleartext, which allows local Apache users to obtain sensitive information by reading the PHP session files.
The ValidateUserLogon function in provider/libserver/ECSession.cpp in Zarafa 5.00 before 7.1.8 beta2 allows remote attackers to cause a denial of service (crash) via vectors related to "a NULL pointer of the username."