Hack history / 2021 / Hack or exploit
Compound V2
Hack or exploit on Sep 29, 2021 · Arithmetic Error
IN REVIEWSOURCES DISAGREE ON DATE OR LOSS · 4 SOURCES
Lost
$147M
sources: $80M to $147M
Returned
none listed
as the sources state it
Rank
#39
among thefts by dollars lost
What happened
Compound V2's Comptroller had a conditional logic bug when Proposal 62 activated on September 29-30, 2021. An off-by-one error (> instead of >=) in the COMP distribution calculation allowed users to claim far more tokens than intended.
In review: possible duplicate within one source; sources disagree on the loss.
Details
- Date
- Sep 29, 2021
- Kind
- Hack or exploit
- Method
- Arithmetic Error
- How in
- Smart contract bug
- Target
- DeFi protocol
- Chains
- Ethereum
- Audit (rekt.news)
- unaudited
Related incidents
Compound 2024 · Hack or exploit · undisclosed
Compound 2024 · Hack or exploit · undisclosed
Compound 2024 · Hack or exploit · $660K
Compound Labs 2023 · Hack or exploit · undisclosed
Compound 2021 · Hack or exploit · $68.8M
Compound 2024 · Hack or exploit · undisclosed
Compound 2024 · Hack or exploit · $660K
Compound Labs 2023 · Hack or exploit · undisclosed
Compound 2021 · Hack or exploit · $68.8M
Cite this page
SwanBluechip, "Compound V2 hack, Sep 29, 2021: $147M lost", Crypto hack history, https://swan-hack-tracker.pages.dev/history/i/ht28e5cd3591/ (data as of 2026-11-01).