Gravity Bridge, a Cosmos-native cross-chain protocol, was the target of a compromised key attack, leading to the theft of approximately $5.4 million this weekend. This latest security breach joins the growing list of exploits that have occurred in the decentralized finance (DeFi) space so far in 2026.
Gravity Bridge hack traced to key compromise signing: researcher
On Saturday, May 31, blockchain sleuth Spectre marked that Gravity Bridge might have been exploited by what he described as a major compromise. For context, a signing key compromise refers to the unauthorized disclosure or theft of a cryptographic key, which allows an attacker to then use it to decrypt sensitive information, forge digital signatures, or gain unauthorized access to systems and, as in this case, funds.
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The analyst revealed that the haul included crypto assets worth approximately $5.4 million, including $4.3 million in USDC, 274 wrapped Ether worth approximately $553,000, $434,000 in USDT, and 14.16 PAXG tokens priced at approximately $64,000. According to security firm PeckShield, the bad guy laundered some of the stolen money through the ExchangeNOW and Binance exchanges, but still owns more than 2,100 Ether (worth about $4.23 million).
The team behind Gravity Bridge confirmed the attack on Saturday and said validators and orchestrators should suspend operations while they investigate the exploit. “Thanks to the quick action of validators, the bridge is currently halted while the investigation continues,” the protocol announced in a subsequent social media post.
Gravity Bridge is a cross-chain protocol that works by locking tokens on the Ethereum network and creating direct replicas of the crypto assets on the Cosmos network, relying on validator signatures to authorize each transfer. Therefore, the protocol would consider even spoofed transactions as legitimate if a bad actor obtains the correct signing keys.
If this Gravity Bridge incident is confirmed as a major compromise, it would join the ongoing pattern of crypto bridge attacks, where breaches are typically embedded in access controls rather than the underlying smart contract code. This pattern can be observed in most recent exploits, with the $292 million Kelp DAO attack being a notable incident.
Crypto hacks continue to pile up in 2026
As previously mentioned, the $5.4 million Gravity Bridge hack joins the growing list of hacks that have rocked the crypto industry, especially the DeFi sector, in 2026. More specifically, bridges appear to have been soft targets for attackers during this period.
Specifically, a report from TRM Labs identified April 2026 as the most hacked month, with the highest number of incidents in crypto history. These attacks include the aforementioned $292 million Kelp DAO hack and Drift Protocol’s $285 million loss.
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