Heap overflow

In MongoDB libbson 1.7.0, the bson_iter_codewscope function in bson-iter.c miscalculates a bson_utf8_validate length argument, which allows remote attackers to cause a denial of service (heap-based buffer over-read in the bson_utf8_validate function in bson-utf8.c), as demonstrated by bson-to-json.c.