Asterisk is an open source private branch exchange and telephony toolkit. Prior to versions 18.26.4 and 18.9-cert17, RTP UDP ports and internal resources can leak due to a lack of session termination. This could result in leaks and resource exhaustion. This issue has been patched in versions 18.26.4 and 18.9-cert17.
https://github.com/asterisk/asterisk/security/advisories/GHSA-557q-795j-wfx2
https://github.com/asterisk/asterisk/pull/1406
https://github.com/asterisk/asterisk/pull/1405
https://github.com/asterisk/asterisk/commit/eafcd7a451dcd007dddf324ac37dd55a4808338d
https://github.com/asterisk/asterisk/commit/0278f5bde14565c6838a6ec39bc21aee0cde56a9