Provide references for CVE-2021-33056.
Where can I find more information about CVE-2021-33056?
References are available at: https://github.com/BelledonneCommunications/belle-sip/commit/116e3eb48fe43ea63eb9f3c4b4b30c48d58d6ff0, https://github.com/BelledonneCommunications/belle-sip/compare/4.5.15...4.5.20.