September 2026: The Approval Layer Was Exploited
Crypto lost $742.0M across 33 incidents in September 2026, almost three times August's $255.5M and the biggest month of the year so far. Bitget's $387M hack and Liquid Network's $320M exploit account for about 95% of that, with the other 31 incidents adding up to $35.0M.
In August, the prices going into contracts were wrong. In September, attackers went after the systems that approve transactions in the first place.
Here's the month in security 馃憞
September 2026 losses by category
| Category | Loss | Incidents |
| Private key / hot-wallet compromise | ~$396.02M | 6 |
| Bridge and cross-chain (unbacked mints, bridge logic) | ~$326.05M | 5 |
| Malicious governance protocol | ~$9.30M | 2 |
| Oracle / price manipulation | ~$4.28M | 4 |
| Social engineering (impersonation) | ~$2.08M | 1 |
| Access control | ~$1.91M | 5 |
| Token and share accounting | ~$1.89M | 3 |
| Protocol logic (swap, reward) | ~$0.45M | 6 |
| Input validation | ~$0.05M | 1 |
| Total (Sep 1 to 30) | ~$742.0M | 33 |
Source: DefiLlama
Hacks of the month
Bitget, ~$387M (Sep 24). The attacker used a zero-day in a third-party security product to get inside Bitget's network, then wrote forged withdrawal requests straight into the wallet backend, which Bitget's signing system approved as normal. Over almost three hours, 26 transfers drained hot and warm wallets across XRPL, Ethereum, Zcash, Tron, and several EVM chains. Bitget says its $464M user protection fund will cover the loss, and North Korea is the suspected attacker.
Source | Hypernative 路 BlockSec 路 Fortune 路 Bitget
Liquid Network, ~$320M (Sep 6). A bug in the cache Liquid's nodes used to skip re-checking range proofs, there since 2016, let two different inputs produce the same cache key. The attacker used that to get an invalid proof treated as already verified, minted 3,998.5 L-BTC with nothing behind it, and redeemed it for real BTC within 36 minutes. Self-described whitehats returned about 3,400 BTC the next day, and Blockstream has said it will cover the remaining gap in the peg.
Source | TRM Labs 路 The Crypto Times 路 Coinpaprika
Astroport and Drop, ~$9.3M (Sep 22). Both protocols had multisigs on their contracts, but Neutron's chain governance can reassign any contract's admin, and that power sits above anything an app sets up. The attacker bought enough NTRN to pass a proposal for roughly $20K, then migrated ten contracts to their own code and drained them in 24 minutes. The official postmortem puts the net loss at around $2.23M.
Source | Protos 路 GoPlus 路 Cosmos Hub Forum 路 Postmortem
Nostra, ~$3.5M (Sep 17). It followed the same pattern as Tectonic and Moonwell in August, where a thinly traded governance token was pumped and then used as collateral. NSTR's price went from about $0.006 to $49.50 on Starknet, and the attacker borrowed around $3.5M against it before Nostra paused the market.
Source | Shattered 路 The Crypto Times
Offchain: the breaches came through vendors.
Trezor's breach at its fulfillment provider ShipMonk grew to 81,000 customers, exposing names, phone numbers, and home addresses that ShipMonk had told Trezor were deleted.
Source | BleepingComputer
A few days later, attackers abused Brevo's SSO setup to take over 138 email marketing accounts and sent 347,000 Trezor users a fake security alert asking for their wallet backup phrases.
Source | SecurityWeek
Separately, a joint advisory from the FBI and allied agencies tied the WaterPlum fake job interview campaign to North Korea, after malicious coding tests infected more than 30,000 devices and moved $10.7M in crypto.
Source | Infosecurity Magazine
The pattern across the month.
Bitget's signer, Liquid's verification cache, and Neutron's governance all exist to decide whether something should go through, and in each case the attacker found a cheap way to get a yes. A few things worth adding to the review list:
Limit what can reach your signer. Bitget's attacker got in through a compromised third-party security product, took a high-level credential to an internal system, and used it to push forged withdrawals that the signer treated as legitimate. Every tool and credential with a path to signing belongs in the threat model.
Review the full stack, not just the contracts. Liquid's bug sat in node-level infrastructure, outside any smart contract, and survived a partial patch five weeks before the exploit.
Know what sits above your multisig. If a governance vote can migrate your contracts, the cost of buying that vote belongs in your threat model. DefiLlama has 8 governance attacks on record for 2026, compared with 1 in all of 2025.
Disclaimer
This report aggregates publicly reported information as of the publication date and may be revised as investigations evolve and post-mortems are released. Recommendations are general guidance. Verify against primary sources before acting on any specific claim.
About This Series
Quantstamp publishes the Security Beat monthly. We've conducted 1,300+ audits and secured $500B+ in digital assets across 250+ clients, including Ethereum Foundation, Aave, Polymarket, Ethena, Visa, OpenSea, Maker, Curve, Compound, and Lido. If you'd like to chat about anything security-related or request an audit, reach out.
