IT Blog


Critical exim security update

A privilege escalation vulnerability exists in Exim, the mail transfer agent used by cPanel & WHM.
All MNX Solutions customers have been patched, and are no longer vulnerable to this privilege escalation vulnerability.
If you are not an MNX Solutions customer, you should read the following page for details on how to correct the problem:
To resolve and work around the issue, for Linux-based systems cPanel has issued new Exim RPMs. The new version of Exim locks configuration file locations to the /etc/exim prefix as well as disabling use of the -D flag. Server Owners are strongly urged to upgrade to the following Exim RPM versions:

  • Systems configured to use Maildir: Exim 4.69-25
  • Systems configured to use mbox (deprecated): Exim 4.63-4

Exim RPMs will be distributed through cPanel’s package management system. All cPanel & WHM servers receiving updates automatically will receive the updated Exim RPM during normal update and maintenance operations (upcp). If you prefer to install the update right now, please run the following in a root shell:
On cPanel & WHM FreeBSD servers, Exim is an unmanaged install performed from the Ports system. To apply a like setup on FreeBSD systems, server administrators will need to perform the following manual configuration:

  • Remove WITHOUT_ALT_CONFIG_PREFIX=yes from /etc/make.conf
  • Add the following to /var/db/ports/exim/options

SEDLIST+= -e ‘s,^(ALT_CONFIG_PREFIX=).*,1/etc/exim,’
SEDLIST+= -e ‘s,^# (DISABLE_D_OPTION=),1,’

  • Change directory to /usr/ports/mail/exim
  • Execute ‘make deinstall’
  • Execute ‘make install’

Caution: the above changes have potential to be undone by /scripts/checkmakeconf, and updates to the Exim port. An upcoming version of cPanel & WHM 11.28 will resolve this for FreeBSD users.