sendmail (SL4)

Synopsis: Low: sendmail security and bug fix update
Issue Date: 2011-02-16
CVE Numbers: CVE-2009-4565

Sendmail is a Mail Transport Agent (MTA) used to send mail between

A flaw was found in the way sendmail handled NUL characters in the
CommonName field of X.509 certificates. An attacker able to get a
carefully-crafted certificate signed by a trusted Certificate Authority
could trick sendmail into accepting it by mistake, allowing the attacker to
perform a man-in-the-middle attack or bypass intended client certificate
authentication. (CVE-2009-4565)

The CVE-2009-4565 issue only affected configurations using TLS with
certificate verification and CommonName checking enabled, which is not a
typical configuration.

This update also fixes the following bugs:

* Previously, sendmail did not correctly handle mail messages that had a
long first header line. A line with more than 2048 characters was split,
causing the part of the line exceeding the limit, as well as all of the
following mail headers, to be incorrectly handled as the message body.

* When an SMTP-sender is sending mail data to sendmail, it may spool that
data to a file in the mail queue. It was found that, if the SMTP-sender
stopped sending data and a timeout occurred, the file may have been left
stalled in the mail queue, instead of being deleted. This update may not
correct this issue for every situation and configuration. Refer to the
Solution section for further information. (BZ#434645)

* Previously, the sendmail macro MAXHOSTNAMELEN used 64 characters as the
limit for the hostname length. However, in some cases, it was used against
an FQDN length, which has a maximum length of 255 characters. With this
update, the MAXHOSTNAMELEN limit has been changed to 255. (BZ#485380)

All sendmail users should upgrade to these updated packages, which contain
backported patches to correct these issues. After installing this update,
sendmail will be restarted automatically.


– Scientific Linux Development Team