Wiktionary
exploitation film
n. A film that relies on lurid subject matter for its appeal.
Wikipedia
Exploitation film
An exploitation film is a film which attempts to succeed financially by exploiting current trends, niche genres, or lurid content.
Exploitation films are generally low-quality " B movies". Even so, they sometimes attract critical attention and cult followings. Some of these films, such as Night of the Living Dead (1968), set trends and become historically important.