This was posted today by Asterisk. It relates to a SIP Crash Vulnerability that was discovered last week and patched today.
We recommend you update your FreePBX Distro system to the latest version. For more information on upgrading your FreePBX Distro please see http://www.freepbx.org/forum/freepbx-distro/distro-discussion-help/release-versions and make sure you upgrade to version 188.8.131.52-2
For any beta customers on 184.108.40.206-1 please upgrade to the latest Beta version as outlined here. http://www.freepbx.org/forum/freepbx-distro/distro-discussion-help/beta-release-versions