Provide references for CVE-2018-9918.
Where can I find more information about CVE-2018-9918?
References are available at: https://usn.ubuntu.com/3638-1/, https://github.com/qpdf/qpdf/commit/b4d6cf6836ce025ba1811b7bbec52680c7204223, https://github.com/qpdf/qpdf/issues/202.