Provide references for CVE-2021-21375.
Where can I find more information about CVE-2021-21375?
References are available at: https://github.com/pjsip/pjproject/security/advisories/GHSA-hvq6-f89p-frvp, https://github.com/pjsip/pjproject/commit/97b3d7addbaa720b7ddb0af9bf6f3e443e664365, https://lists.debian.org/debian-lts-announce/2021/04/msg00023.html, https://lists.debian.org/debian-lts-announce/2021/05/msg00020.html, https://security.gentoo.org/glsa/202107-42.