An issue was discovered in PHP before 5.6.36, 7.0.x before 7.0.30, 7.1.x before 7.1.17, and 7.2.x before 7.2.5. exif_read_data in ext/exif/exif.c has an out-of-bounds read for crafted JPEG data because exif_iif_add_value mishandles the case of a MakerNote that lacks a final '\0' character.