Nomic Bridge Bug Freezes 36% of Osmosis allBTC [2026]

A Bitcoin bridge exploit that most of the crypto market didn’t even notice as it happened is now reshaping how the Cosmos ecosystem talks about wrapped BTC. On September 9, 2026, Osmosis froze minting, redemptions, deposits and withdrawals for its synthetic Bitcoin asset, allBTC, after discovering that a bug in the Nomic bridge had let an attacker mint tens of Bitcoin worth of fake collateral back in June. The twist: the exploit sat undetected for 74 days before anyone noticed the hole in the books.

The dollar figure is small by 2026 cryptocurrency standards, somewhere between $1.8 million in confirmed frozen funds and roughly $3.1 million in total exposure. But the mechanics matter more than the number. This is a story about how a bug in one chain’s bridge logic can quietly drain trust from an entire basket asset built on top of it, and about why Cosmos’s Inter-Blockchain Communication protocol, the plumbing that makes IBC transfers possible, keeps getting blamed for failures that live one layer up in the bridges that plug into it.

What Happened: Nomic’s nBTC Bug Freezes Osmosis allBTC

Nomic is a Cosmos-based chain purpose-built to bridge native Bitcoin into the Cosmos ecosystem, issuing a token called nBTC as a 1:1 voucher for BTC locked on its side. Osmosis, the largest decentralized exchange in Cosmos, pools nBTC together with other Bitcoin representations into a basket token called Alloyed BTC, or allBTC, meant to give traders one liquid synthetic BTC instead of juggling several thinly-traded wrapped versions.