Ethereum was the hardest-hit blockchain in the first half of 2026, according to a new report from security firm Blockaid. The losses were driven largely by key compromises — not protocol bugs or flash-loan attacks. Solana replaced Arbitrum as the network with the second-highest losses during the period.
Key compromises drove the losses
Blockaid's data points to a clear pattern: attackers went after private keys, not smart contract code. That shifts the blame from the blockchain itself to the projects and users who manage access. The report doesn't name specific incidents, but the trend is consistent with a broader industry focus on wallet security and multi-sig setups.
Solana climbs to second
Solana's jump to the No. 2 spot marks a change from H2 2025, when Arbitrum held that position. The shift suggests that as activity on Solana grows — whether from DeFi, memecoins, or infrastructure — so does the attack surface. Arbitrum, meanwhile, saw its relative share of losses decline, though it remains a major target.
What the numbers mean for security teams
For exchanges, custodians, and dApp developers, the message is blunt: key management is the weak link. A single compromised key can drain millions faster than any exploit. Blockaid's findings reinforce the need for hardware security modules, threshold signatures, and regular key rotation. The report covers H1 2026; the second half is already underway, and the same risks haven't gone away.
