KelpDAO & LayerZero: Incident Report
On April 18, 2026, a forged cross-chain message drained $292 million from KelpDAO's LayerZero bridge in under 46 minutes.
Preliminary attribution points to North Korea's Lazarus Group, specifically the TraderTraitor unit responsible for the $285 million Drift Protocol exploit. Across those two attacks combined, Lazarus Group has drained more than $575 million from DeFi in under three weeks.
How the Attack Unfolded
LayerZero V2 uses Decentralized Verifier Networks (DVNs) to validate cross-chain messages. LayerZero OApps configure their own security stack by choosing which DVNs must attest to a message's validity before it's accepted on the destination chain. The model supports multi-verifier redundancy. KelpDAO's rsETH bridge used a 1-of-1 DVN setup, with LayerZero Labs as the sole verifier. One forged attestation was enough to authorize withdrawals.
In the weeks before April 18, attackers compromised two RPC nodes that LayerZero's DVN relied on to confirm transaction validity, replacing the software with malicious versions that validated fraudulent transactions while reporting accurate data to every other system. Standard monitoring was not able to detect the compromise. On April 18 at around 17:30 UTC, attackers launched a DDoS attack against the remaining healthy nodes, forcing the DVN to failover to poisoned infrastructure. With the DVN now reading only from compromised nodes, attackers submitted a forged LayerZero V2 packet. The DVN verified it as legitimate. KelpDAO's bridge released 116,500 rsETH, worth roughly $292 million and representing 18% of the token's circulating supply, from escrow to the attacker's address.
The attacker immediately deposited the stolen rsETH across seven wallets on Aave V3 Core as collateral and borrowed approximately 126,000 WETH, around $236 million, to convert the stolen collateral into liquid ETH before markets could be frozen. Kelp's emergency pauser multisig froze core contracts 46 minutes after the drain, successfully blocking two follow-up attempts totaling approximately $200 million.
How the Damage Spread
The exploit left rsETH on Layer 2 networks partially unbacked, because the mainnet reserves held in the LayerZero bridge had been drained.
Stolen rsETH had entered Aave V3 as collateral before the freeze, and the resulting uncertainty about its backing created bad debt the protocol is still working through. A joint incident report from Aave Labs and LlamaRisk outlines two scenarios: if KelpDAO were to socialize losses across all rsETH holders globally, the token would face an estimated 15% depeg and approximately $124 million in bad debt for Aave; if losses were confined to rsETH on Arbitrum and Mantle, Aave's exposure rises to roughly $230 million. The Aave Protocol Guardian froze rsETH markets across V3 and V4, set LTV to zero, and halted new borrowing within hours of the exploit. Aave's own contracts weren't compromised and its risk systems operated normally. The problem was impaired collateral entering the system before it could be stopped.
Beyond Aave, the downstream effects were substantial. $8.45 billion left Aave in deposits over 48 hours, with total DeFi TVL dropping $13.4 billion in the two days following the exploit, from roughly $99.5 billion to $86.1 billion. By April 27, it had fallen further to roughly $84 billion. Stargate Finance saw $400 million in outflows within 12 hours. Lido identified $21.6 million in rsETH exposure in their EarnETH Vault and paused related deposits. The Arbitrum Security Council later froze 30,766 ETH, approximately $71 million, linked to the attacker.
A Systemic Vulnerability in a Cross-Chain Ecosystem
Dune Analytics published a dashboard following the exploit showing that 47% of LayerZero OApps, roughly half of approximately 2,665 active contracts analyzed over the previous 90 days, operate with the same 1-of-1 DVN configuration that enabled this attack. Another 45% use 2-of-2. Only about 5% use 3-of-3 or higher.
LayerZero has confirmed zero contagion from the KelpDAO exploit to other applications. But every OApp running a 1-of-1 DVN configuration is, at this point, one operational security failure away from a similar outcome. LayerZero has since announced it won't sign messages for 1-of-1 OApps and now recommends a minimum of three to five independent DVNs. That's the right response, and it should have been the default from the start.
DeFi United: The Industry Responds
In the days after the KelpDAO/LayerZero exploit, an emergency coalition formed. Aave service providers, alongside Kelp DAO, Ether.fi, LayerZero, Mantle, and others, launched DeFi United, a coordinated recovery effort with the goal of fully restoring rsETH's backing and preventing bad debt from impacting lenders on Aave.
According to the Aave DAO governance proposal published April 24, the original backing shortfall stood at approximately 163,183 ETH. Four recovery streams have since reduced that gap materially: Kelp froze 40,373 rsETH (equivalent to roughly 43,168 ETH), the Arbitrum Security Council froze 30,766 ETH linked to the attacker, and the attacker's remaining leveraged positions on Aave and Compound represent an estimated additional 14,168 WETH through liquidation. Combined, those streams account for roughly 87,955 ETH recovered or recoverable and reduce the residual funding gap to approximately 75,081 ETH.
The DeFi United tracker shows contributions and commitments from across the ecosystem covering that gap. On April 27, Aave announced that leading Ethereum stewards Consensys and co-founder Joseph Lubin had joined DeFi United with up to 30,000 ETH in financial support. Major contributors also include Mantle (30,000 ETH via credit facility), Aave DAO (25,000 ETH pending governance vote), Stani Kulechov personally (5,000 ETH), Ether.fi (5,000 ETH), Lido Finance (2,500 stETH), Kelp DAO (2,000 ETH), and Golem Foundation (1,000 ETH), alongside the Arbitrum Security Council's 30,766 ETH (pending a separate Arbitrum governance vote for release). Total commitments stand at roughly $161 million. Aave Founder & CEO Stani Kulechov also confirmed the recovery target had been reached, subject to pending votes and successful execution.
Does Nexus Mutual Cover This?
The root cause of the KelpDAO/LayerZero exploit was an operational security failure inside LayerZero's infrastructure. As we covered in our Resolv and Drift incident reports, Nexus Mutual currently does not offer any cover products that protect members against operational security failures (read about our future plans in the next section). We also don’t cover bridge risk because it creates systemic risk that would exceed our internal risk limits.
There is a coverage angle that does apply here. Nexus Mutual Protocol Cover's liquidation failure clause protects against bad debt created on lending protocols where an impaired asset is listed as collateral. The bad debt materializing on Aave and other lending protocols from the rsETH impairment falls within that scope.
Anyone who held Protocol Cover for Aave before April 18 would be covered for losses resulting from liquidation failure, assuming bad debt is ultimately realized and socialized to lenders. How that plays out depends on how KelpDAO determines to allocate the shortfall, and we'll provide an update as that becomes clearer.
No claims have been received as a result of this event. We'll provide an update if that changes.
How Nexus Mutual is Addressing the Operational Security Gap
This is now the third major operational security-driven loss event in 2026. Resolv lost approximately $23-25 million when an attacker compromised an AWS signing key and minted 80 million unbacked USR tokens. Drift lost $285 million through a six-month social engineering campaign that ended in a multisig key compromise. This time, KelpDAO lost $292 million through an infrastructure compromise that exploited a bridge with no redundant verification.
In all three cases, the attackers exploited the infrastructure due to missing security checks. Operational security failures have been responsible for close to 50% of all losses in DeFi and CeFi since 2016, and the pace in 2026 is accelerating. We've been working with experts at the Security Alliance to build a cover product for teams that are certified against industry best practices and remain in compliance.
When the KelpDAO/LayerZero incident unfolded on a Saturday night, Nexus Mutual members were already asking for guidance on how to secure their onchain assets within hours. As Hugh Karp, Nexus Mutual's Founder, wrote in his response to the incident: "Hackers don't take a day off. In a space that is always on 24/7, you need security partners who aren't waiting for Monday to get back to work." Cover is part of the security stack you build before the worst happens.
TheDAO Fund named Hugh one of just 200 recipients of an ETHSecurity Badge, an onchain credential for the top 200 contributors to Ethereum's security infrastructure. Nexus Mutual has been covering DeFi since 2019.
Our rigorous underwriting and strict adherence to risk limits is why we're still here while most competitors have come and gone. We can't cover everything, but we're committed to covering more, safely.
Look for more updates on the operational security cover product in the months ahead. If you want to know what cover is available for your current positions, reach out at nexusmutual.io/contact.
