What happened
On October 12–13, 2026, Autheo Network’s native THEO token on Base suffered an unbacked cross-chain mint exploit resulting in the unauthorized creation of 19 million THEO tokens. The attacker dumped the minted tokens into liquidity pools on Base for ~298.9 ETH (~$750,000 USD net exploit profit), causing THEO's market price to crash by over 92%.
The incident stemmed from a vulnerability in the cross-chain message verification system/trusted relayer for Autheo Network. This permitted an "unbacked cross-chain mint" on Base, allowing the attacker to mint 19 million THEO tokens out of thin air from the null address without locking corresponding assets on the source chain. The attacker subsequently dumped 19M THEO across DEX pools (including Hydrex Integral) on Base, extracting ~298.9 ETH (~$750K USD).
The attacker then bridged 280.45 ETH to Ethereum Mainnet via Relay bridge. While initial security alerts reported a $1.76M loss based on the destination wallet's total balance of 700.8 ETH, on-chain tracing verified that the address already held ~400.8 ETH prior to the attack, establishing the actual net exploit loss at ~298.9 ETH (~$750,000 USD). Following the attack, Autheo Network issued an urgent security notice instructing users to stop trading and bridging THEO while investigations remain ongoing.
Protocol details
Evidence
Build your security review skills
Work through hands-on labs covering real exploit mechanics, review techniques, and defensive patterns.
