An example system in accordance with an aspect of the present disclosure includes a cache engine, a validate engine, and an access engine. The cache engine is to cache, into an address cache of an object reference, an object address corresponding to an object, in response to performing a lookup of the object via at least one indirection. The validate engine is to validate that an object ID of the object located at the cached object address corresponds to a reference object ID that is stored in the object reference and associated with the object. The access engine is to access the object via a lookup of the object address cached in the address cache of the object reference, in response to validating the reference object ID.