Hack history / 2025 / Hack or exploit
GMX V1 EVM
Hack or exploit on Jul 9, 2025 · Reentrancy
IN REVIEWSOURCES AGREE ON DATE AND LOSS · 5 SOURCES
Lost
$42M
dollars at the time
Returned
$40M
95% of the loss, as a source states it
Rank
#119
among thefts by dollars lost
What happened
On July 9, 2025, GMX V1 perpetuals on Arbitrum suffered a $42M exploit through reentrancy in executeDecreaseOrder(). Attacker exploited the assumption that _account is an EOA, using a contract to reenter, manipulate short positions, inflate GLP price, and profit via redemptions; attacker returned funds July 12, keeping a $5M bounty.
In review: possible duplicate within one source.
Details
- Date
- Jul 9, 2025
- Kind
- Hack or exploit
- Method
- Reentrancy
- How in
- Smart contract bug
- Target
- DeFi protocol
- Chains
- Arbitrum, Ethereum
After the theft
- Returned by the attacker
- yes, amount not stated
“attacker returned funds July 12, keeping a $5M bounty.” (DefiLlama) - Bounty paid
- yes, amount not stated
“Following negotiation, the attacker returned all stolen funds and received a $5 million bounty.” (SlowMist Hacked)
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Unverified_35bc 2025 · Hack or exploit · $7K
StepHeroNFTs 2025 · Hack or exploit · $90K
Unverified_35bc 2025 · Hack or exploit · $7K
Cite this page
SwanBluechip, "GMX V1 EVM hack, Jul 9, 2025: $42M lost", Crypto hack history, https://swan-hack-tracker.pages.dev/history/i/ht0601341fba/ (data as of 2026-11-01).