Definition

Flash Loan Attack

Meaning ⎊ Exploiting uncollateralized instant loans to manipulate prices and drain protocol liquidity in one block.
Greeks.liveApril 14, 2026

Flash Loan Attack

A flash loan attack is a type of exploit where a malicious actor borrows a massive amount of capital without collateral, performs a series of actions, and repays the loan within a single transaction block. If the loan is not repaid by the end of the block, the entire transaction is reverted as if it never happened.

Attackers use these loans to manipulate the price of assets on decentralized exchanges, creating arbitrage opportunities that drain liquidity pools. Because the capital is borrowed instantly, the attacker can influence the price of a token significantly.

This manipulation can trigger cascading liquidations in other protocols, allowing the attacker to profit from the resulting instability. It represents a unique form of market manipulation enabled by the atomic nature of blockchain transactions.

These attacks have become a significant concern for the security of DeFi protocols. They highlight the dangers of relying on single-source price oracles.

Sybil Attack Vectors
Flash Loan Exploit
Flash Loan Attack Simulation
Flash Loan Price Manipulation
Flash Loan
Sybil Attack Resistance
Flash Loan Manipulation
Flash Loan Resistance

Glossary

Sandwich Attack Vector

Action ⎊ A Sandwich Attack Vector represents a form of front-running specifically targeting decentralized exchange (DEX) transactions, exploiting the visibility of pending transactions within the mempool.

Price Oracle Attack

Vulnerability ⎊ A price oracle attack exploits the vulnerability inherent in smart contracts that rely on external data feeds for asset pricing.

Vega Convexity Attack

Context ⎊ A Vega Convexity Attack, within cryptocurrency derivatives, specifically options, represents a sophisticated trading strategy exploiting the non-linear relationship between option prices (Vega) and implied volatility, coupled with the convexity inherent in option pricing models like Black-Scholes.

Flash Loan Attack Protection

Protection ⎊ Flash loan attack protection refers to the implementation of specific safeguards within smart contracts and decentralized finance protocols to prevent exploitation via uncollateralized, instant loans.

Flash Loan Attack Resilience

Algorithm ⎊ Flash Loan Attack Resilience centers on the proactive development and deployment of smart contract code designed to detect and neutralize malicious exploitation attempts leveraging flash loans.

51% Attack Cost

Cost ⎊ A 51% Attack Cost represents the economic expenditure required to gain control of a majority of the hashing power within a Proof-of-Work blockchain network, enabling the attacker to manipulate transaction history.

Re-Entrancy Attack Prevention

Countermeasure ⎊ Re-entrancy attack prevention focuses on mitigating vulnerabilities within smart contracts where a malicious contract recursively calls back into the vulnerable contract before the initial execution completes, potentially draining funds.

Pre-Flash Loan Era

Arbitrage ⎊ The Pre-Flash Loan Era, preceding approximately 2020, characterized a landscape where arbitrage opportunities in decentralized finance (DeFi) were largely inaccessible to automated strategies due to capital inefficiency.

Oracle Attack Vector

Oracle ⎊ An oracle, within decentralized finance, represents a bridge between blockchain-based smart contracts and external, real-world data sources.

Flash Loan Resilience

Algorithm ⎊ Flash Loan Resilience, within decentralized finance, represents the capacity of a smart contract or trading strategy to maintain operational integrity and profitability despite the transient, substantial liquidity injections and withdrawals characteristic of flash loans.