Provide references for CVE-2021-23180.
Where can I find more information about CVE-2021-23180?
References are available at: https://github.com/michaelrsweet/htmldoc/issues/418, https://bugzilla.redhat.com/show_bug.cgi?id=1967041, https://ubuntu.com/security/CVE-2021-23180, https://github.com/michaelrsweet/htmldoc/commit/19c582fb32eac74b57e155cffbb529377a9e751a.