Hack history / 2020 / Hack or exploit

Cover Protocol

Hack or exploit on Dec 28, 2020 · Arithmetic Error

IN REVIEWSOURCES DISAGREE ON DATE OR LOSS · 4 SOURCES

Lost

$9.4M

sources: $3M to $9.4M

Returned

none listed

as the sources state it

Rank

#316

among thefts by dollars lost

What happened

Cover Protocol's Blacksmith contract was exploited on December 28-29, 2020, due to incorrect memory/storage reference in reward calculation logic, allowing unbounded minting of approximately 40 quintillion COVER tokens. Funds were returned by a white hat hacker.

In review: sources disagree on the loss.

Details

Date: Dec 28, 2020
Kind: Hack or exploit
Method: Arithmetic Error
How in: Smart contract bug
Target: DeFi protocol
Chains: Ethereum
Audit (rekt.news): Arcadia Group

After the theft

Returned by the attacker: yes, amount not stated
“Funds were returned by a white hat hacker.” (DefiLlama)

Reported by

Related incidents

SYFI 2020 · Hack or exploit · $250K

Cite this page

SwanBluechip, "Cover Protocol hack, Dec 28, 2020: $9.4M lost", Crypto hack history, https://swan-hack-tracker.pages.dev/history/i/ht16ccb341a5/ (data as of 2026-10-31).

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