Hack history / 2020 / Hack or exploit
Uniswap V1
Hack or exploit on Apr 18, 2020 · Reentrancy
ATTACK TX CONFIRMED ON CHAINSOURCES AGREE ON DATE AND LOSS · 3 SOURCES
Lost
$220K
dollars at the time
Returned
none listed
as the sources state it
Rank
#1,460
among thefts by dollars lost
What happened
An attacker exploited a reentrancy vulnerability in Uniswap V1's imBTC liquidity pool using ERC777's callback mechanism. By calling deposit, triggering the ERC777 callback before balance updates, and immediately withdrawing, the attacker could drain tokens from the pool at artificial prices. The Consensys team had discovered the vulnerability in 2019 but no exploitable ERC777 token existed until imBTC launched.
Details
- Date
- Apr 18, 2020
- Kind
- Hack or exploit
- Method
- Reentrancy
- How in
- Smart contract bug
- Target
- DeFi protocol
- Chains
- Ethereum
Reported by
Related incidents
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dForce Lending 2020 · Hack or exploit · $25M
Origin Protocol 2020 · Hack or exploit · $7.7M
Akropolis 2020 · Hack or exploit · $2M
Uniswap (Phishing Attack) 2022 · Hack or exploit · $8.2M
dForce Lending 2020 · Hack or exploit · $25M
Origin Protocol 2020 · Hack or exploit · $7.7M
Akropolis 2020 · Hack or exploit · $2M
Cite this page
SwanBluechip, "Uniswap V1 hack, Apr 18, 2020: $220K lost", Crypto hack history, https://swan-hack-tracker.pages.dev/history/i/ht4a248068db/ (data as of 2026-10-31).