Running validators secures Ethereum and other PoS networks, but it carries a distinct risk called slashing. Slashing is the network’s penalty for actions that threaten consensus, such as double-signing, a validator attesting to two conflicting blocks, and surround voting, when a validator’s later vote contradicts its own earlier one. Slashing is a severe penalty to make attacking the chain prohibitively expensive, so a validator can lose a chunk of its stake and get ejected from the network.

However, most slashing isn’t malicious. It usually traces back to an operator mistake, like a backup server that signs at the same time as the primary, or a botched migration between setups. The real danger is when many validators share infrastructure or a single node operator, one error can slash them all at once and turn a small individual penalty into a large aggregate loss.