Hack history / Monthly reports / 2021-09
Crypto hacks and thefts, September 2021
Thefts are hacks, exploits, phishing, scams and rug pulls, in dollars at the time. A single source for $500M or more waits for a second source before it counts.
Taken
$222.1M
23 thefts
vs the month before
−75%
−75% ($876.2M)
vs a year earlier
−48%
−48% ($429.3M)
Largest thefts
Compound V2 29 · Arithmetic Error$147MVee Finance 21 · Spot Price Manipulation$35MpNetwork 19 · Spoofed Event Log$13MpNetwork 20 · Contract Vulnerability$12MDAO Maker Vesting 03 · Improper Access Control$4MSiren 03 · Reentrancy$3.5MZabu Finance 11 · Deposit Logic Flaw$3.2MJayPegs Automart 17 · Frontend Compromise$3.1MNowSwap 14 · Arithmetic Error$1.1MBitfinex 27 · Handle inventory defects with fixed precision and extended value range$148K
How attackers got in
Smart contract bug 14$159M
Price, oracle and governance 2$35M
Bridge and cross-chain 3$25M
Keys, accounts and infrastructure 2$3.1M
Phishing and scams 1$5K
Other 1$0
By chain
Ethereum 7$155.2M
Avalanche 2$38.2M
Bitcoin 2$25M
BNB Chain 1$13M
Polygon 1$3.5M
not stated 9$253K
EOS 1$26K
Fantom 1$0
By target
DeFi protocol 8$209.9M
Bridge 1$12M
Centralized exchange 1$148K
not stated 13$131K
Collapses and frauds, counted apart
1 cases, $17K.
Cite this page
SwanBluechip, "Crypto hacks and thefts, September 2021", Crypto hack history, https://swan-hack-tracker.pages.dev/history/m/2021-09/ (data as of 2026-10-31).