The (1) t1_parse_font_matrix function in type1/t1load.c, (2) cid_parse_font_matrix function in cid/cidload.c, (3) t42_parse_font_matrix function in type42/t42parse.c, and (4) ps_parser_load_field function in psaux/psobjs.c in FreeType before 2.5.4 do not check return values, which allows remote attackers to cause a denial of service (uninitialized memory access and application crash) or possibly have unspecified other impact via a crafted font.
The product receives input or data, but it does not validate or incorrectly validates that the input has the properties that are required to process the data safely and correctly.