Matcha Meta disclosed a security breach on Sunday after attackers exploited SwapNet’s router contract, one of the protocol’s primary liquidity sources. The warning was direct: users who had previously approved token access to that contract could still face losses and should revoke approvals at once.
Security firms published different loss estimates. CertiK put the amount stolen at $13.3 million, while PeckShield said the damage on Base was about $16.8 million. Matcha Meta said the weakness came from SwapNet rather than its own infrastructure, placing the incident in the growing category of third-party contract risk inside DeFi execution flows.
Exploit centered on arbitrary call in SwapNet contract
CertiK said the attacker used an “arbitrary call in 0xswapnet contract” that made it possible to transfer funds already approved to the contract. That detail matters. The losses were not described as a direct wallet compromise, but as abuse of standing token approvals once the contract flaw was triggered.
PeckShield added that the attacker swapped about 10.5 million USDC for roughly 3,655 ETH and had started bridging funds to Ethereum. Once funds begin moving across networks, recovery and monitoring usually become more complicated, especially when the assets have already been converted.
Smart-contract flaws accounted for 30.5% of 2025 exploits
The breach fits a larger pattern. SlowMist reported that 30.5% of all exploits in 2025 came from smart-contract vulnerabilities, representing 56 separate incidents. Automated execution is part of DeFi’s appeal, but the same design can turn a coding mistake into a large-scale loss, particularly where protocols depend on non-custodial liquidity providers or on-chain pricing oracles.
The same report said account takeovers and hacked X accounts made up 24% of total attacks. In other words, contract risk remains a major source of damage even as social-account and account-level compromises continue to hit the sector.
AI tools are now finding DeFi weaknesses worth millions
Security research is also shifting. Last December, AI models including Claude Opus 4.5, Claude Sonnet 4.5, and GPT-5 identified potential smart-contract weaknesses worth about $4.6 million across various protocols. The implication is practical: the same class of tools can accelerate vulnerability discovery for defenders, while also speeding up exploit research on the other side.
The Matcha Meta incident came shortly after other DEX-related breaches. Six days earlier, Makina Finance lost $4.13 million from its DUSD/USDC liquidity pool on Curve after a compromised data feed. Earlier still, CoWSwap disclosed a breach involving GPv2Settlement smart contracts that siphoned about $180,000. Taken together, these cases show how external solvers, liquidity providers, and broad contract permissions can open critical attack paths inside otherwise sophisticated protocols.