Provide references for CVE-2021-4026.
Where can I find more information about CVE-2021-4026?
References are available at: https://huntr.dev/bounties/c6dfa80d-43e6-4b49-95af-cc031bb66b1d, https://github.com/bookstackapp/bookstack/commit/b4fa82e3298a15443ca40bff205b7a16a1031d92.