Provide references for CVE-2021-21392.
Where can I find more information about CVE-2021-21392?
References are available at: https://pypi.org/project/matrix-synapse/, https://github.com/matrix-org/synapse/security/advisories/GHSA-5wrh-4jwv-5w78, https://github.com/matrix-org/synapse/pull/9240, https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/TNNAJOZNMVMXM6AS7RFFKB4QLUJ4IFEY/.