AES, or Advanced Encryption Standard, is a block cipher that supports various block sizes between 128 and 256 bits in that are multiples of 32 bits.
There is no known practical attacks against AES, though related key attacks do exist, and some of them are only for the reduced-round version. Related key attacks
Other indirect attacks exist, such as side-channel attacks, but often they require the adversary to obtain information about the processor.