Blockchain security firm Hacken said in a new assessment that roughly half of circulating USDT, or about $91.3 billion on Tron, is controlled by a 2-of-3 multi-signature contract that lacks built-in delays, cancellation procedures, or dependable revocation mechanisms.

According to Hacken, an attacker that compromises two of the three required keys could change contract ownership, mint tokens, freeze addresses, clear frozen balances, or set transfer fees, without needing to access user wallets. The firm said those permissions stem from the contract’s administrative design rather than from any compromise of customer funds.

Hacken also said Tether uses the same set of six signature keys across three other chains: Ethereum, Avalanche, and Celo. In the firm’s view, that creates a risk that a key compromise or signer failure could extend beyond a single network. The report assigned USDT a cybersecurity score of 3.3 out of 10, citing the lack of automatic reserve-proof checks and the absence of a token minting cap in the smart contract.

The report drew a distinction between technical control risk and balance-sheet strength. Hacken noted that once signers authorize a transaction, the contract can mint tokens without an on-chain reserve-proof check. Separately, stablecoin rating agency Bluechip upgraded Tether’s company rating from D to C, citing a KPMG audit showing that, as of December 31, 2025, Tether’s reserves exceeded liabilities by $6.8 billion.

Hacken said it has not yet completed a comparable assessment of Circle’s USDC. It also said Bluechip’s previous B+ rating for USDC was based on an outdated methodology and should not be used as a direct technical comparison with the USDT contract assessment.

Why It Matters

The report puts attention on a part of stablecoin infrastructure that is often less visible than reserve disclosures: who controls issuer contracts and how quickly those powers can be exercised. For a token widely used in trading, transfers, and exchange settlement, admin-key design and cross-chain operational controls matter alongside reserve quality.

The story also highlights that stablecoin risk is not one-dimensional. A reserve surplus or stronger company rating does not address every contract-level security question, and a low technical security assessment does not by itself show a live solvency problem. For the broader market, the gap between financial backing and smart-contract governance is becoming harder to ignore.