Key Takeaways:
A Wanchain-operated bridge between Cardano and BNB Chain lost about 515 million NIGHT tokens valued at $9 million in an exploit, BlockSec said.
"The TreasuryCheck validator combines 14 fields of varying lengths without adding clear separators, which could allow different data sets to produce the same signed message," BlockSec's Phalcon team said in a preliminary analysis of the onchain Plutus V2 code.
The incident triggered heavy selling of Midnight's native governance token, sending NIGHT down about 31 percent to $0.0186 as of July 21, according to CoinGecko data. BlockSec said the bridge's TreasuryCheck validator may have been vulnerable to a signature reuse attack, where an attacker reorganizes field values while keeping the same signed message to authorize a different transaction.
The Midnight Foundation said the exploit was isolated to Wanchain's third-party bridge infrastructure and did not affect the Midnight network's validators, consensus system or core protocol. Wanchain had not published a full technical postmortem at the time of writing.
BlockSec's initial investigation pointed to a possible flaw in how the TreasuryCheck validator creates messages for signing. The security firm said the contract already contained Cardano's SerialiseData function, but the bridge did not appear to use it when building the signature hash. Encoding each field with clear boundaries would prevent two different data sets from producing an identical signed message, BlockSec said.
Wanchain originally launched cross-chain support for NIGHT between Cardano and BNB Chain in December 2025. The bridge uses threshold-signature relayers to connect Cardano with EVM and non-EVM networks, according to Cardano's official ecosystem directory.
The Midnight Foundation initially said it was investigating reports of an incident involving the Wanchain bridge and bridged NIGHT. It later clarified that the event was limited to Wanchain's infrastructure. "The incident is isolated to the Wanchain Cardano–BNB bridge and does not involve the Midnight Network itself," the foundation said.
NIGHT is Midnight's native governance token and also generates DUST, the network resource used for transactions and smart contract execution. Midnight lists the token's total supply at 24 billion. The project launched its mainnet in March 2026 and operates as a privacy-focused Cardano partner chain with a dual-token economic model.
The reported Wanchain incident follows several bridge attacks in 2026. Taiko halted parts of its network after a verification problem affected its bridge system. Other recent incidents involved Verus Protocol, Axelar-linked routes and older Aztec infrastructure. Bridge security remains a recurring problem across crypto, as cross-chain infrastructure often holds large pools of assets while relying on complex verification systems between networks that cannot communicate directly.
This article is for informational purposes only and does not constitute investment advice.
