A NULL pointer dereference in the ext4_dir_en_get_name_len function in include/ext4_dir.h of lwext4 1.0.0 allows attackers to cause a denial of service by supplying a specially crafted EXT4 filesystem image with malformed directory entries. During directory iteration, the code may fail to validate the directory entry pointer before accessing the name_len field, resulting in a segmentation fault. This affects versions based on (or equivalent to) the 2016-era codebase (1.0.0).