SAND Bridge Exploit: The Sandbox Isolates Base and BNB Chain After Unbacked Token Mint

The Sandbox has suspended SAND bridging on Base and BNB Smart Chain after an attacker exploited its cross-chain infrastructure to mint unbacked tokens, isolating SAND on both networks as the project investigates the breach.

The team said the underlying SAND locked on Ethereum remains secure and continues to back legitimate bridged tokens. Ethereum and Polygon were not affected, and no user wallets were compromised.

The Sandbox estimated the actual impact at less than 0.01% of SAND's total supply. That figure is sharply different from the nominal amount of fraudulent tokens created: security firm Blockaid estimated roughly $49 billion in face-value SAND had been minted across more than 400 transactions. PeckShield separately flagged about 14.9 billion SAND minted to two addresses.

Base and BNB Chain SAND Isolated

The project disabled transfers both to and from Base and BNB Smart Chain, preventing the newly minted tokens from being redeemed through the bridge or moved back toward the collateral held on Ethereum.

Users were advised not to buy, sell or trade SAND on the two affected networks because their liquidity has been compromised. The Sandbox is also preparing a snapshot from before the incident and said qualifying liquidity providers will be compensated.

The episode comes as cross-chain infrastructure remains a recurring attack surface. Coinpaper's recent review of July crypto hacks found several bridge-related incidents during a month in which reported crypto theft reached $247.4 million.

Similar vulnerabilities have continued into August. A recent Coreum bridge flaw allowed nearly 200,000 XRP to be drained without compromising XRP Ledger validator keys, while Harmony was forced to halt its bridge after a suspected unauthorized mint of roughly 4 billion ONE tokens.

SAND Transfers Paused on Major Korean Exchanges

The security incident also prompted action from major South Korean exchanges. Bithumb suspended SAND deposits and withdrawals at 11:11 a.m. Korea time on August 22, with Upbit following one minute later. The exchanges cited security concerns under South Korea's Virtual Asset User Protection Act.

Upbit initially suspended transfers for Ethereum-based SAND as well, although The Sandbox subsequently said the Ethereum token was never exposed to the vulnerability.

The event adds another security challenge for a project that remains one of the better-known names among metaverse coins. SAND serves as the utility and transaction token across The Sandbox ecosystem, which includes virtual land, digital assets and creator-built experiences.

The Sandbox said it will publish a full post-mortem after completing its investigation. Until the bridge is restored, SAND on Base and BNB Smart Chain remains effectively separated from the project's unaffected Ethereum and Polygon markets.