In libavformat/nsvdec.c in FFmpeg 2.4 and 3.3.3 a DoS in nsv_parse_NSVf_header() due to lack of an EOF (End of File) check might cause huge CPU consumption. When a crafted NSV file which claims a large \table_entries_used\ field in the header but does not contain sufficient backing data is provided the loop over 'table_entries_used' would consume huge CPU resources since there is no EOF check inside the loop.