Asterisk may be configured to only allow specific audio
or video codecs to be used when communicating with a
particular endpoint. When an endpoint sends an SDP offer
that only lists codecs not allowed by Asterisk, the offer
is rejected. However, in this case, RTP ports that are
allocated in the process are not reclaimed.
This issue only affects the PJSIP channel driver in
Asterisk. Users of the chan_sip channel driver are not
affected.
As the resources are allocated after authentication,
this issue only affects communications with authenticated
endpoints.