Nomic is a bridge protocol that issues nBTC, an IBC-transferable Bitcoin voucher, into the Cosmos ecosystem. Osmosis, the Cosmos decentralized exchange, is the entity named in the discovery claim, having accepted those vouchers as valid inbound transfers.
Osmosis took 74 days to discover a Nomic exploit that minted roughly 40 BTC worth of unbacked nBTC on its network, exposing a wrapped-Bitcoin accounting failure that left the protocol’s pooled Bitcoin token only partially collateralized. The delay, disclosed in a September 10, 2026 governance proposal, is the central concern: counterfeit Bitcoin vouchers circulated for more than two months before a chain halt forced a backing check.
WHAT TO KNOW
- The incident report describes a Nomic exploit involving roughly 40 BTC of unbacked nBTC minted on Osmosis.
- Osmosis took 74 days to discover the exploit, according to the protocol’s governance proposal.
What the 40-BTC Nomic exploit report says
Nomic is a bridge protocol that issues nBTC, an IBC-transferable Bitcoin voucher, into the Cosmos ecosystem. Osmosis, the Cosmos decentralized exchange, is the entity named in the discovery claim, having accepted those vouchers as valid inbound transfers. For related coverage, see Albuquerque Bans Bitcoin ATMs: 45 Days to Remove Them.
On June 25, 2026, the Nomic bridge minted 40.650602 BTC worth of nBTC on Osmosis without corresponding Bitcoin held in reserve, according to the governance proposal. This figure represents unbacked issuance rather than a confirmed net theft or recovered funds. For related coverage, see Blockstream Rejects Ransom After Alleged 4,000 BTC Liquid Hack.
The linked forensic report places the Osmosis credit at 21:50:08 UTC on June 25, in block 64910685, involving 25 packets carrying consecutive sequences 9286 through 9310. It attributes the flaw to missing sender authorization and self-transfer escrow accounting inside Nomic, and states that IBC replay protection was not bypassed; Osmosis accepted valid proofs of what were, in fact, unbacked Nomic commitments. For related coverage, see Bitcoin Takes 42% of Repeat Crypto Purchases: Paybis.
Notably, the report says no Bitcoin was stolen directly from Nomic’s on-chain reserve. Its reconstructed checkpoint ledger reconciles to 0.746000 BTC with a stated 0.000000 BTC discrepancy, a finding of the author-affiliated analysis rather than an independently rerun audit. The exploit inflated the voucher supply rather than draining custodied coins.
The reported 74-day delay in discovering the exploit
The counterfeit vouchers went undetected for a full quarter. The governance proposal states that Nomic halted on September 7, 2026, and that the halt prompted the backing check that exposed the mint after 74 days; June 25 to September 7 independently counts as 74 calendar days.
74 days
Discovery is distinct from disclosure. The forensic report notes that an emergency release, v31.1.0, reached one-third voting power on September 7 at 23:15 and crossed the two-thirds threshold on the morning of September 8, staging the response rather than resolving it in a single step. Osmosis publicly acknowledged the incident on September 9.
Osmosis described the mechanism in its own statement, framing it as a double-spend that produced false vouchers accepted downstream.
Recently, we became aware of an exploit on the Nomic chain. The exploit allowed the attacker to double-spend nBTC, allowing them to send false vouchers to Osmosis. Osmosis and IBC were not compromised, as the bug was in a custom forwarding mechanism on Nomic.
39.84 nBTC of the…
— Osmosis 🧪 (@osmosis) September 9, 2026
Source: @osmosis on X
The detection gap sits within wider scrutiny of Cosmos-ecosystem disclosure. Protos, which reported the delay, explicitly described a separate Cosmos EVM module bug as unrelated to the Nomic incident, cautioning against conflating the two. That framing recalls how earlier cross-chain security episodes played out, such as the disputed Blockstream Liquid hack.
What remains unverified about the Nomic exploit
The damage concentrated inside allBTC, Osmosis’s alloyed Bitcoin token that pools multiple wrapped-BTC assets into a single share. The September 10 proposal lists 110.570944 allBTC shares outstanding against 70.731198 BTC of real WBTC and cbBTC collateral, with 39.839746 BTC of unbacked nBTC still counted as collateral, producing a reported backing ratio of 63.97%.
63.97%
The emergency upgrade froze an attacker-linked position of 22.65060846 allBTC, but freezing is not seizure. The proposal seeks governance authorization to transfer those frozen shares to the Liquidity subDAO via a future software upgrade and to draw on community assets to restore backing. As proposal author JohnnyWyles wrote, the freeze preserves the asset but does not allocate it; applying it to the shortfall is a governance decision, not an automatic consequence of v31.1.0.
To close the gap, the proposal counts 12.4838 allBTC in the community pool and a residual funding shortfall of 4.7053 BTC, which it proposes covering by intercepting a pending USDC.noble-to-allUSDC liquidity redeployment. It also excludes 0.797700 BTC of nBTC held outside the alloy, identifying that external float as Nomic’s liability with no redemption possible while the chain stayed halted. Osmosis separately detailed the mechanics of its 22.65 BTC freeze after the forwarding bug.
Fund-flow tracing points to laundering. The forensic report traces 671.1 ETH into 33 Tornado Cash deposits across June 25 and June 28, a figure Protos summarized as roughly 671 ETH and one not independently checked against explorer transactions in this reporting. No regulator action or legal ruling has been established, and the proposed transfer of frozen funds is a protocol and software-upgrade matter, not a court order.
Several outcomes remain unconfirmed. The restoration plan is a proposal, not an approved or executed recapitalization, and no fetched evidence establishes governance passage or resumed nBTC redemption. Reports that Nomic is no longer actively maintained rest on public commit activity and remain, according to unconfirmed reports, uncorroborated. The absence of these details here does not mean they are unavailable publicly.
For Bitcoin holders, the episode underscores that wrapped and bridged BTC carries counterparty and accounting risk absent from base-layer coins. Native Bitcoin’s supply is governed by proof-of-work issuance and periodic difficulty adjustments that no custom forwarding module can silently inflate; a bridged voucher’s backing, by contrast, depends entirely on off-chain reconciliation. That distinction between a scarce base asset and a claim on reserves is the core lesson of the 74-day gap.
Disclaimer: This article is for informational purposes only and does not constitute financial or investment advice. Cryptocurrency and digital asset markets carry significant risk. Always do your own research before making decisions.
