TAC (Cosmos EVM precompile) hack — August 2026

TAC, an EVM network that brings DeFi applications to TON and Telegram users, lost close to 3 billion TAC from its staking pool on 22 August 2026 and halted validator block production at block 24,671,475 to stop the attack. It was the third chain drained through the same defect in the shared cosmos/evm staking precompile, after MANTRA on 20 August and alongside KiiChain the same evening.

The figure recorded is $950,000: what roughly 1.2 billion of the stolen tokens actually fetched when the attacker sold them on BNB Chain. The remaining tokens were not sold at anything like that rate, and no party has published a dollar value for the full 3 billion taken. Recording the realised figure rather than a spot-price conversion of the whole amount is deliberate — the token's market could not absorb the position, and a nominal valuation of the full take would overstate the loss several times over.

The defect was not in TAC's own code. It sits in the shared Cosmos EVM module the chain runs unmodified. Cosmos Labs first received the report in April 2026, concluded production networks were not at risk, and shipped the fix through its silent patch process; it later acknowledged that call was wrong. Across six chains between 20 and 25 August the attackers realised about $5.72m, split roughly evenly between decentralised and centralised venues.

The network remained halted with no published restart timetable, and its TON bridge stayed dark. This is a separate incident from the May 2026 bridge exploit recorded elsewhere in this registry.