cyrus-imapd-2.2 - denial of service

It was discovered that cyrus-imapd, a highly scalable mail system designed
for use in enterprise environments, is not properly parsing mail headers
when a client makes use of the IMAP threading feature. As a result, a NULL
pointer is dereferenced which crashes the daemon. An attacker can trigger
this by sending a mail containing crafted reference headers and access the
mail with a client that uses the server threading feature of IMAP.

For the oldstable distribution (lenny), this problem has been fixed in
version 2.2.13-14+lenny6.

For the stable distribution (squeeze), this problem has been fixed in
version 2.2.13-19+squeeze3.

For the testing (wheezy) and unstable (sid) distributions, this problem has been
fixed in cyrus-imapd-2.4 version 2.4.11-1.

We recommend that you upgrade your cyrus-imapd-2.2 packages.