SingularityNET Bridge Hack Drains $16.77M in AI Crypto

Home » SingularityNET Bridge Hack Drains $16.77M in AI Crypto

September 24, 2026 0

Quick answer: On September 19–20, 2026, an attacker stole a signing key controlling the SingularityNET bridge between Ethereum and Cardano and used it to mint unauthorized tokens across an entire cluster of AI-crypto projects — Fetch.ai (FET), SingularityNET (AGIX), NuNet (NTX), and World Mobile Chain (WMTx). Roughly 2.3 billion tokens were created out of thin air, and the attacker walked away holding an estimated $16.77 million in AGIX and WMTx alone, on top of about $1.53 million in FET drained directly from a conversion contract. Fetch.ai says its core FET contracts were never compromised and has paused AGIX-to-FET conversions and its Ethereum-side bridge while the investigation continues. NTX, the token hit hardest, lost as much as 95% of its value within a day. This wasn’t a smart-contract bug in the traditional sense — it was a stolen key with no spending limits behind it, and that distinction matters for how you think about which DeFi tokens you’re willing to hold.

What Actually Happened, Hour by Hour

Security incidents in crypto tend to get messy in the retelling, so it helps to lay this one out in order. The first confirmed move came at 20:21 UTC on September 19, when the attacker drained 8.7 million FET tokens — worth about $1.53 million at the time — from Fetch.ai’s TokenConversionManagerV3 contract on Ethereum. That contract exists to let holders convert between FET and its predecessor tokens, and it processed the withdrawal in a single Ethereum block.

Twenty-eight minutes later, at 20:50 UTC, the same attacker minted 408.53 million NuNet (NTX) tokens using a compromised NuNet authorization key. Then, over the following day, the attack widened further: 260 million AGIX and roughly 53.8 million WMTx tokens were minted on Ethereum, expanding the incident well beyond Fetch.ai and into the broader ASI Alliance ecosystem that SingularityNET, Fetch.ai, and several partner networks belong to.

By the time security researchers had pieced together the full picture, the unauthorized supply across AGIX, NTX, CGV, and WMTx totaled an estimated 2.3 billion tokens. Not all of that was liquid or sellable — a lot of it sat in wallets that got frozen or deactivated once teams caught on — but the attacker’s realized holdings still worked out to roughly $16.77 million, with the bulk of that in AGIX (about 198.3 million tokens, worth close to $14.42 million).

The Root Cause: One Signing Key, No Guardrails

Here’s the part that should worry anyone who thinks of bridge exploits as purely a smart-contract problem. According to security firm SlowMist, the TokenConversionManagerV3 contract relied on nothing more than a single ECDSA signature from one externally-owned account to authorize conversions. No spending limits. No burn-proof verification requiring that an equivalent amount of the source token actually be destroyed before new tokens got minted on the other side. Just one key, and whoever held it could sign off on essentially unlimited minting.

That’s a design choice, not a bug in the strict sense — the code did exactly what it was written to do. The problem is that “do exactly what a valid signature says” becomes catastrophic the moment that signature falls into the wrong hands. Fetch.ai’s own account of events described it as “a stolen SingularityNET bridge authorizer key used to produce a valid signature for the converter call,” which is a fairly stark admission that the failure point wasn’t clever exploit code — it was basic key custody.

This pattern isn’t new, and it isn’t rare, either. TRM Labs data on 2026 crypto hacks found that infrastructure and key-compromise incidents made up only about 15% of the year’s total hack count, yet accounted for roughly 76% of all stolen funds. Smart-contract bugs get more headlines because there are more of them, but when a private key or signing authority gets compromised, the damage tends to be disproportionately larger. This incident fits that pattern almost exactly.

Who Said What: The Official Response

Fetch.ai moved fairly quickly to draw a line between what was and wasn’t affected. In a statement issued around 06:51 UTC on September 20, the team said its core FET contracts “were not under threat and that FET continues to operate normally,” framing the attack as one that “targeted SingularityNET contracts, primarily the SingularityNET Bridge between Ethereum and Cardano.” As precautionary steps, AGIX-to-FET conversions were paused, the Ethereum-side bridge was halted, and affected wallets and contracts were deactivated in coordination with SingularityNET.

World Mobile Chain, whose WMTx token got caught up in the same minting spree, said it was “contacting exchanges to freeze affected deposits and working with security partners to revoke minting authorities.” The team also initiated a pre-exploit snapshot of token balances and advised holders not to interact with WMTx contracts while the investigation was ongoing.

One notable gap, as of the most recent reporting: SingularityNET itself — the project whose bridge was actually compromised — hadn’t published its own standalone incident statement, leaving much of the public communication to Fetch.ai and the affected partner projects. That’s worth watching, since the entity that controlled the compromised key is presumably the one best positioned to explain exactly how it was stolen.

The Market Reaction Tells Its Own Story

Markets are usually the fastest judge of how serious an exploit really is, and the reaction here was uneven in a telling way. FET, whose contracts weren’t directly compromised, fell only about 5% over 24 hours — a real but modest hit, consistent with a token that lost some supply to a drain but didn’t have its issuance mechanism broken.

NTX told a very different story. Because the attack involved minting new NTX out of nothing rather than draining existing tokens, the resulting supply shock crashed the token roughly 65% to 95% depending on the exchange and timeframe measured, with some sources citing an all-time low around $0.00004075. WMTx dropped about 43%. That gap between FET’s modest decline and NTX’s near-collapse is the market pricing in a crucial distinction: draining a bridge is a one-time theft, but breaking a token’s minting authority undermines confidence in its entire supply going forward.

Editor’s update, September 24, 2026: AGIX itself — the token most directly tied to the compromised bridge, and the one holding the largest share of the attacker’s stolen value — saw an even sharper move than the FET and WMTx figures above suggest. SingularityNET’s native token briefly cratered from roughly $0.0775 to an all-time low of $0.0006841 within about an hour of the exploit, a flash crash of more than 99%, before clawing back most of that ground over the following days. As of this update, AGIX trades back near $0.078, close to where it sat before the attack, even though the exploit itself and the attacker’s holdings remain unchanged. NTX has not bounced the same way: it’s still down more than 70% over the past week and trading close to its post-exploit lows. That contrast — a fast recovery for AGIX against a lasting hit for NTX — reinforces the point above that markets punish tokens differently depending on how much doubt an incident casts on future issuance.

Exchange-level responses followed quickly. Bitget and KuCoin both suspended FET deposits and withdrawals as a precaution while the situation stabilized, a standard move that protects the exchange from processing further compromised transactions but also temporarily traps legitimate holders’ funds in place.

A Reader’s-Eye View of the Chaos

Picture checking your portfolio app on a Saturday night and seeing NuNet down 80% in an hour, with no obvious news yet explaining why. Your first instinct is probably to assume it’s a rug pull or a routine crash, not a cross-chain minting exploit rooted in a completely different project’s bridge. That confusion is exactly what happened to a lot of holders here — NTX wasn’t the project that got hacked, but it absorbed some of the worst damage because its token happened to share infrastructure and trust assumptions with SingularityNET’s bridge.

If you’d tried to sell into that drop immediately, you’d have been selling into a market that hadn’t yet priced in the full picture — some exchanges were still processing normal trades while others had already frozen deposits. That’s the uncomfortable reality of fast-moving DeFi security incidents: the information you need to make a rational decision usually arrives well after the price has already moved.

Why This Matters Beyond the AI-Crypto Niche

It’s tempting to file this under “niche AI token drama” and move on, especially if you don’t hold FET, AGIX, NTX, or WMTx. But the underlying lesson generalizes. Cross-chain bridges connecting multiple tokens through shared authorization infrastructure are only as strong as the weakest key in that chain. When several independent projects — Fetch.ai, SingularityNET, NuNet, World Mobile — all rely on the same bridge authorizer for conversions between their ecosystems, a single compromised key becomes a single point of failure for all of them simultaneously.

That’s a structural risk that exists well outside the ASI Alliance. Any time you see multiple tokens described as “interoperable” or “cross-chain convertible” through a shared bridge, ask yourself who holds the keys to that bridge, and what happens if just one of those keys leaks. The answer, in this case, was a $16.77 million answer.

Frequently Asked Questions

What exactly is the SingularityNET bridge exploit?

It’s a September 19–20, 2026 incident in which an attacker stole a signing key used to authorize the SingularityNET bridge between Ethereum and Cardano, then used that key’s valid signature to drain 8.7 million FET tokens and mint roughly 2.3 billion unauthorized tokens across AGIX, NTX, CGV, and WMTx.

Is my FET, AGIX, or NTX safe right now?

Fetch.ai says core FET contracts were never compromised, and affected wallets and contracts tied to the exploit have been deactivated. That said, AGIX-to-FET conversions and the Ethereum-side bridge remain paused, and the investigation is ongoing, so treat any bridge or conversion interaction involving these tokens with caution until teams confirm it’s fully resolved.

How did the attacker mint tokens without hacking a smart contract?

The contract wasn’t hacked in the sense of exploiting a code flaw. It relied on a single ECDSA signature from one authorized account to approve conversions, with no spending limits or proof that source tokens were actually burned first. Once the attacker had that one key, the contract simply did what it was designed to do — process a validly signed request.

Why did NTX crash so much harder than FET?

FET lost tokens to a drain, which is a fixed, one-time loss. NTX had new tokens minted into existence, which directly undermines confidence in the token’s total supply and future issuance, triggering far heavier selling.

Will affected exchanges or projects make holders whole?

There’s no confirmed compensation plan as of this writing. Some exchanges suspended deposits and withdrawals to limit further damage, and World Mobile took a pre-exploit snapshot that could support some form of remediation, but nothing has been formally announced for reimbursing losses.

What should DeFi investors take away from this beyond the specific tokens involved?

Shared bridge infrastructure across multiple “interoperable” tokens creates a single point of failure. Before trusting a cross-chain conversion mechanism, it’s worth asking what authorization model backs it — a single key, a multisig, or something with built-in spending limits — since that detail predicts how bad a compromise could get.

Sources

Key Takeaways

A stolen SingularityNET bridge authorizer key let an attacker drain 8.7 million FET (~$1.53M) and mint roughly 2.3 billion unauthorized tokens across AGIX, NTX, CGV, and WMTx between September 19–20, 2026.
The attacker’s realized holdings totaled about $16.77 million, concentrated mostly in AGIX (~198.3 million tokens, ~$14.42M).
Fetch.ai says its core FET contracts were unaffected and has paused AGIX-to-FET conversions and its Ethereum-side bridge as a precaution.
NTX crashed roughly 65–95% because new tokens were minted (a supply-integrity failure), while FET fell only about 5% since it was drained, not diluted.
Update (Sept 24, 2026): AGIX briefly flash-crashed over 99% (to an all-time low of $0.0006841) within an hour of the exploit but had recovered to roughly its pre-hack price (~$0.078) within days — unlike NTX, which remains down more than 70% a week later.
TRM Labs data shows infrastructure and key-compromise hacks were about 15% of 2026’s incident count but roughly 76% of stolen funds — this exploit fits that disproportionate-damage pattern closely.
Bitget and KuCoin suspended FET deposits and withdrawals, and SingularityNET itself had not issued a standalone public statement as of the most recent reporting.

This article is for general market education and information purposes only, not financial or investment advice. Token minting incidents like this one can evolve quickly, and figures reported here reflect information available as of publication. Always do your own research, verify current status directly through official project channels, and never interact with paused or disputed contracts based on secondhand reporting alone.

If cross-chain and bridge security is on your radar, our coverage of the Term Finance governance exploit and the Cronos/Tectonic price-manipulation hack covers two very different failure modes worth understanding alongside this one — between the three, you get a fairly complete picture of how DeFi actually breaks in 2026.

Blockchain News