Provide references for CVE-2021-21259.
Where can I find more information about CVE-2021-21259?
References are available at: https://github.com/hedgedoc/hedgedoc/security/advisories/GHSA-44w9-vm8p-3cxw, https://github.com/hedgedoc/hedgedoc/releases/tag/1.7.2, https://github.com/hedgedoc/hedgedoc/commit/35b0d39a12aa35f27fba8c1f50b1886706e7efef, https://github.com/hackmdio/codimd/issues/1648.