Two signing keys govern $91.3 billion in USDT.

For users treating the stablecoin as a dollar substitute, that is custody risk hidden in the plumbing.

Hacken found the Tron contract has no delay or reversal, and reused keys extend the same control to Ethereum, Avalanche and Celo.

Hacken found no breach, but a two-key compromise could still act across every chain at once.

Sources: CoinDesk