Digging deep into Wanchain’s Cardano-BNB Bridge exploit – How $9M NIGHT vanished in hours

Wanchain’s Cardano-BNB Bridge, a cross-chain protocol allowing asset transfers between Cardano [ADA] and other blockchain networks, was allegedly compromised.

This opened doors for attackers to drain up to 515 million NIGHT tokens worth $9 million from the bridge’s treasury. 

As per the investigation, the exploit was induced by a cryptographic vulnerability in the bridge’s TreasuryCheck validator called non-injective signed-message encoding.

Multiple withdrawals lead to the loss of 515 mln NIGHT

For context, each withdrawal request in a secure system is supposed to generate a distinct message. This is to ensure that a validator’s digital signature can only authorize that particular transaction.

However, this vulnerability was possible due to multiple withdrawal requests to generate the same encrypted message.

As a result, the illicit actor was able to secure the ability to authorize phony withdrawals without having access to the validator’s private key. For its part, this was done by reusing a legitimate signature from a legitimate transaction.

Moving ahead, the wrongdoer also laundered the stolen NIGHT tokens to ADA on the Cardano network.

Steps taken and impact on NIGHT

Since then, Wanchain has halted the Cardano-BNB Bridge and begun an investigation. They even confirmed that the incident was restricted to the bridge and had no impact on Midnight’s network or Cardano’s core blockchain. 

Surge in exploits, but hope remains

In fact, in the past week, the crypto space has witnessed multiple exploits wherein the wrongdoer took advantage of a distinct flaw in a decentralized protocol. This included the Allbridge Core, a cross-chain bridge exploit that resulted in the loss of $1.65 million.

Then a perpetual decentralized exchange on Arbitrum called Ostium was the target of an oracle exploit, resulting in the loss of $18 million. Lastly, a malicious governance proposal that was approved resulted in an exploit that cost the BONK ecosystem about $20 million. 

Yet despite an increase in attack frequency, DeFiLlama stated that overall losses dropped precipitously to $1 billion as of July 2026 as compared to $2.135 billion seen in the same period in 2025.

Final Summary

• A cross-chain protocol exploit resulted in the loss of 515 million NIGHT tokens worth $9 million.
• The exploiter earned access to authorize fake withdrawals by reusing a legitimate signature from a legitimate transaction.