From the Mandriva advisory:
The login form in Roundcube Webmail before 0.5.1 does not properly
handle a correctly authenticated but unintended login attempt, which
makes it easier for remote authenticated users to obtain sensitive
information by arranging for a victim to login to the attacker's
account and then compose an e-mail message, related to a login CSRF
issue (CVE-2011-1491).
steps/utils/modcss.inc in Roundcube Webmail before 0.5.1 does
not properly verify that a request is an expected request for an
external Cascading Style Sheets (CSS) stylesheet, which allows remote
authenticated users to trigger arbitrary outbound TCP connections
from the server, and possibly obtain sensitive information, via a
crafted request (CVE-2011-1492).
Cross-site scripting (XSS) vulnerability in the UI messages
functionality in Roundcube Webmail before 0.5.4 allows remote attackers
to inject arbitrary web script or HTML via the _mbox parameter to
the default URI (CVE-2011-2937).
include/iniset.php in Roundcube Webmail 0.5.4 and earlier, when PHP
5.3.7 or 5.3.8 is used, allows remote attackers to trigger a GET
request for an arbitrary URL, and cause a denial of service (resource
consumption and inbox outage), via a Subject header containing only
a URL, a related issue to CVE-2011-3379 (CVE-2011-4078). | 