Multiple vulnerabilities has been discovered and corrected in
cyrus-imapd:

Stack-based buffer overflow in the split_wildmats function in nntpd.c
in nntpd in Cyrus IMAP Server before 2.3.17 and 2.4.x before 2.4.11
allows remote attackers to execute arbitrary code via a crafted NNTP
command (CVE-2011-3208).

Secunia Research has discovered a vulnerability in Cyrus IMAPd,
which can be exploited by malicious people to bypass certain security
restrictions. The vulnerability is caused due to an error within the
authentication mechanism of the NNTP server, which can be exploited
to bypass the authentication process and execute commands intended
for authenticated users by sending an AUTHINFO USER command without
a following AUTHINFO PASS command (CVE-2011-3372).

Packages for 2009.0 are provided as of the Extended Maintenance
Program. Please visit this link to learn more:
http://store.mandriva.com/product_info.php?cPath=149&products_id=490

The updated packages have been patched to correct these issues.