Details for this vulnerability have not been published by NIST at this point. Descriptions from software vendor advisories for this issue are provided below.
An out-of-bounds heap read condition may occur when scanning PDF documents. The defect is a failure to correctly keep track of the number of bytes remaining in a buffer when indexing file data. (CVE-2019-1787)
An out-of-bounds heap read condition may occur when scanning PE files (i.e. Windows EXE and DLL files) that have been packed using Aspack as a result of inadequate bound-checking. (CVE-2019-1789)
An out-of-bounds heap write condition may occur when scanning OLE2 files such as Microsoft Office 97-2003 documents. The invalid write happens when an invalid pointer is mistakenly used to initialize a 32bit integer to zero. This is likely to crash the application. (CVE-2019-1788)