Cronos halted its blockchain after identifying an exploit affecting Tectonic, the lending protocol built on the Cronos ecosystem.

The Cronos Network account said on Sunday that it had identified an exploit in Tectonic and that the network had been halted while it provided updates. Tectonic separately said it was aware of an incident affecting the protocol and was actively investigating, warning users not to interact with the protocol until it confirmed conditions were safe.

The interruption is notable because it moved beyond pausing a single DeFi application and stopped the underlying chain's block production. That can limit an attacker's ability to move assets, but it also freezes normal network activity for users and other applications while validators and developers coordinate a response.

Published reports estimated the loss near $75 million, describing the incident as involving price manipulation around TONIC, Tectonic's token. Tectonic had not confirmed the final loss amount or root cause in its initial public warning, so the exact damage should remain provisional until the team releases a verified postmortem.

The incident adds to a long-running DeFi security problem: lending markets can become exposed when collateral prices, liquidity, oracle design or market controls fail under stress. For Cronos, the immediate questions are when normal block production resumes, how affected funds are handled, and what changes Tectonic makes before users are told it is safe to return.