MetaMask is withdrawing approximately 17,000 validators holding roughly 523,000 ETH after a security breach redirected validator fee rewards to an address funded through Tornado Cash, an Ethereum-based privacy protocol.
According to onchain security researcher Kaden, transaction-fee rewards from 18 of 19 validators that proposed blocks were diverted to the compromised address. The attacker captured approximately 0.36 ETH, though the primary concern centers on how the attacker gained access to alter fee recipients and whether that access extended to validator signing keys, which could trigger slashable penalties.
MetaMask confirmed that part of its infrastructure had been compromised and stated it was exiting affected validators as a precaution while working with clients, partners, and security advisers. The company said it identified no immediate threat to MetaMask wallets and that its staking operation is non-custodial, meaning it does not control clients' withdrawal keys. However, MetaMask has not disclosed the total number of affected validators, whether signing keys were exposed, or whether any slashing has occurred.
Kaden identified 821 potentially affected validators that had not yet exited at the time of analysis, including three among those whose fee rewards were allegedly diverted.
Ethereum's Exit Queue Reaches Nine-Month High
The MetaMask exits are contributing to a broader bottleneck in Ethereum's staking infrastructure. Approximately 773,447 ETH was waiting to exit the validator set, representing the largest withdrawal backlog since December 2025 and exceeding the roughly 476,000 ETH that queued during a surge in May.
At current processing rates, validators face an estimated wait of approximately 13 days and 10 hours to clear the exit queue, followed by an additional 7.6-day withdrawal sweep period.
The queue reflects a built-in Ethereum safeguard rather than a processing limitation. Ethereum restricts how quickly stake can enter or leave the validator set to prevent abrupt changes from destabilizing its proof-of-stake consensus. The current churn rate allows 256 ETH to exit per epoch, with each epoch lasting approximately 6.4 minutes.
For MetaMask-linked validators operating through Lido, the full exit, withdrawal, and re-entry process could take up to 45 days, partly due to an entry queue currently estimated at 27 days.
