The Proof-of-Stake (PoS) Ethereum consensus protocol through 2021-10-19 allows an adversary to cause a denial of service (delayed consensus decisions), and also increase the profits of individual validators, via short-range reorganizations of the underlying consensus chain.

The Proof-of-Stake (PoS) Ethereum consensus protocol through 2021-10-19 allows an adversary to cause a denial of service (long-range consensus chain reorganizations), even when this adversary has little stake and cannot influence network message propagation. This can cause a protocol stall, or an increase in the profits of individual validators.

The Proof-of-Stake (PoS) Ethereum consensus protocol through 2021-10-19 allows an adversary to leverage network delay to cause a denial of service (indefinite stalling of consensus decisions).