Provide references for CVE-2021-4216.
Where can I find more information about CVE-2021-4216?
References are available at: https://bugs.ghostscript.com/show_bug.cgi?id=704834, https://github.com/ArtifexSoftware/mupdf/commit/22c47acbd52949421f8c7cb46ea1556827d0fcbf.