Provide references for CVE-2021-3993.
Where can I find more information about CVE-2021-3993?
References are available at: https://github.com/star7th/showdoc/commit/654e871a3923e79076818a9a03533fe88222c871, https://huntr.dev/bounties/0aa84736-139b-4ae7-becf-604f7f60b1c9.