Provide references for CVE-2021-21393.
Where can I find more information about CVE-2021-21393?
References are available at: https://pypi.org/project/matrix-synapse/, https://github.com/matrix-org/synapse/pull/9321, https://github.com/matrix-org/synapse/pull/9393, https://github.com/matrix-org/synapse/security/advisories/GHSA-jrh7-mhhx-6h88, https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/TNNAJOZNMVMXM6AS7RFFKB4QLUJ4IFEY/.