Asterisk -- multiple vulnerabilities

The Asterisk Development Team reports:

It is possible for a user of the Asterisk Manager Interface to
bypass a security check and execute shell commands when they
should not have that ability. Sending the “Async” header with
the “Application” header during an Originate action, allows
authenticated manager users to execute shell commands. Only
users with the “system” privilege should be able to do this.
On systems that have the Asterisk Manager Interface, Skinny, SIP
over TCP, or the built in HTTP server enabled, it is possible for
an attacker to open as many connections to asterisk as he wishes.
This will cause Asterisk to run out of available file descriptors
and stop processing any new calls. Additionally, disk space can
be exhausted as Asterisk logs failures to open new file
descriptors.