On May 2021, JulSwap was exploited in a flash loan attack, resulting in approximately $1.5M in losses. That makes the JulSwap exploit the 76th largest DeFi incident out of 690 documented in our archive.
Attack Mechanics: How the JulSwap Flash Loan Attack Played Out
Exploit Class Applied to JulSwap
The JulSwap incident on May 27, 2021 is classified as a Flash Loan Attack. Attackers borrow huge amounts via uncollateralised single-transaction loans and manipulate protocol state before repaying in the same block. In the full archive, JulSwap is 1 of 27 documented flash loan attack incidents.
JulSwap in Context
At $1.5M, the JulSwap exploit is a significant ($1M–$10M) event compared to the largest same-class incident in our archive — PolterFinance (2024) at $7M.
Prior Flash Loan Attack Before JulSwap
The nearest flash loan attack incident before JulSwap was DODO, 80 days earlier on March 8, 2021 ($700K lost). The same exploit class surfaced again within the flash loan attack attack surface.
JulSwap Vulnerability Signature
The primary source categorises the JulSwap exploit specifically as “Flash Loan”. This narrower label is entity-specific: it reflects how the JulSwap contract failed, rather than the broad flash loan attack pattern alone.
Impact & Recovery for JulSwap
JulSwap Loss Figure
The JulSwap exploit caused $1,500,000 in losses — a significant ($1M–$10M) incident and the 6th largest of 37 documented in 2021. This single incident represents 0.7% of all tracked losses that year.
Where JulSwap Sits Among Flash Loan Attack Attacks
Ranked by loss size, JulSwap is the 2nd largest of 27 flash loan attack incidents documented. That puts the JulSwap loss above the class average of $577.3K.
Timeline Since the JulSwap Incident
The JulSwap exploit occurred 4.9 years ago (1,783 days). The contract, its fork-block, and the attack transaction remain on-chain and forensically reproducible.
Primary Reference for JulSwap
Public post-mortem / on-chain analysis for the JulSwap incident: view source.
FAQ
How much did JulSwap lose?
The JulSwap exploit in May 2021 resulted in $1,500,000 in losses — the 6th largest of 37 DeFi incidents that year.
When did the JulSwap hack happen?
The JulSwap exploit was recorded on May 27, 2021 — 1,783 days ago.
What type of exploit hit JulSwap?
The JulSwap incident is classified as a Flash Loan Attack. Attackers borrow huge amounts via uncollateralised single-transaction loans and manipulate protocol state before repaying in the same block.
How common is the Flash Loan Attack pattern seen at JulSwap?
Our archive contains 27 documented flash loan attack incidents. The JulSwap incident is one of them.
How does JulSwap compare to the largest Flash Loan Attack attack?
The largest flash loan attack incident in our archive is PolterFinance (2024) at $7M. The JulSwap loss is $1.5M.
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