Are all of the species hyenas endangered?

No, not all hyena species are endangered. According to the International Union for Conservation of Nature (IUCN), the conservation status of the four hyena species are:

Spotted Hyena (Crocuta crocuta): Least Concern

Striped Hyena (Hyaena hyaena): Near Threatened

Brown Hyena (Parahyaena brunnea): Near Threatened

Aardwolf (Proteles cristata): Least Concern

While the spotted hyena is considered to be of least concern, the striped and brown hyenas are both listed as near threatened due to habitat loss, conflict with humans, and hunting.