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Security

Flash Loan Attack

An exploit where an attacker borrows a large amount of tokens via an uncollateralized flash loan, uses the borrowed funds to manipulate protocol state (typically distorting oracle prices or satisfying collateral requirements), extracts profit from the manipulated state, and repays the loan — all within a single atomic transaction. On Solana, flash loans are possible because transactions are atomic: if any instruction fails, the entire transaction reverts including the loan. Defenses include using time-weighted oracle prices, enforcing borrowing caps, and requiring multi-slot settlement.

IDflash-loan-attack
Plain meaning

Plain meaning

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An exploit where an attacker borrows a large amount of tokens via an uncollateralized flash loan, uses the borrowed funds to manipulate protocol state (typically distorting oracle prices or satisfying collateral requirements), extracts profit from the manipulated state, and repays the loan — all within a single atomic transaction. On Solana, flash loans are possible because transactions are atomic: if any instruction fails, the entire transaction reverts including the loan. Defenses include using time-weighted oracle prices, enforcing borrowing caps, and requiring multi-slot settlement.

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Flash Loan Attack (flash-loan-attack)
Category: Security
Definition: An exploit where an attacker borrows a large amount of tokens via an uncollateralized flash loan, uses the borrowed funds to manipulate protocol state (typically distorting oracle prices or satisfying collateral requirements), extracts profit from the manipulated state, and repays the loan — all within a single atomic transaction. On Solana, flash loans are possible because transactions are atomic: if any instruction fails, the entire transaction reverts including the loan. Defenses include using time-weighted oracle prices, enforcing borrowing caps, and requiring multi-slot settlement.
Related: Oracle Manipulation, Front-Running, Flash Loan
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Branch

Oracle Manipulation

An attack in which an adversary artificially distorts the price or data reported by an on-chain oracle — most commonly by executing large trades to move a spot-price oracle (such as one based on a single AMM's instantaneous price) — and then exploits protocols that consume that price for lending, liquidation, or derivatives settlement before the oracle corrects. Flash-loan-amplified oracle manipulation is particularly dangerous: an attacker borrows a large sum atomically, moves the price, exploits the manipulated price, and repays the loan in one transaction. Defenses include using time-weighted average prices (TWAPs), aggregating multiple independent oracle sources (e.g., Pyth's aggregate confidence interval, Switchboard's weighted median), and enforcing staleness and confidence-band checks on every consumed price feed.

OraclePrice Feed
Open term
Branch

Front-Running

An attack where an adversary observes a pending or not-yet-finalized transaction (e.g., a large swap or NFT mint) and submits a competing transaction with higher priority fees or via validator relationships to execute before the victim's transaction, profiting from predictable price impact. On Solana, transactions are not held in a public mempool the same way as in Ethereum — leaders receive transactions privately — but front-running is still possible through Jito's block engine bundle mechanism, validator collusion, or by monitoring gossip. Slippage tolerance parameters and commit-reveal schemes are the primary application-level defenses.

MEV (Maximal Extractable Value)Sandwich Attack
Open term
Branch

Flash Loan

An uncollateralized loan that must be borrowed and repaid within the same transaction. If the loan isn't repaid by transaction end, the entire transaction reverts atomically. Flash loans enable arbitrage, collateral swaps, and self-liquidation with zero capital. On Solana, Solend and MarginFi offer flash loans; they're also used in sandwich attacks.

Lending ProtocolArbitrage
Open term
Next concepts to explore

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Security

Oracle Manipulation

An attack in which an adversary artificially distorts the price or data reported by an on-chain oracle — most commonly by executing large trades to move a spot-price oracle (such as one based on a single AMM's instantaneous price) — and then exploits protocols that consume that price for lending, liquidation, or derivatives settlement before the oracle corrects. Flash-loan-amplified oracle manipulation is particularly dangerous: an attacker borrows a large sum atomically, moves the price, exploits the manipulated price, and repays the loan in one transaction. Defenses include using time-weighted average prices (TWAPs), aggregating multiple independent oracle sources (e.g., Pyth's aggregate confidence interval, Switchboard's weighted median), and enforcing staleness and confidence-band checks on every consumed price feed.

Open term
Security

Front-Running

An attack where an adversary observes a pending or not-yet-finalized transaction (e.g., a large swap or NFT mint) and submits a competing transaction with higher priority fees or via validator relationships to execute before the victim's transaction, profiting from predictable price impact. On Solana, transactions are not held in a public mempool the same way as in Ethereum — leaders receive transactions privately — but front-running is still possible through Jito's block engine bundle mechanism, validator collusion, or by monitoring gossip. Slippage tolerance parameters and commit-reveal schemes are the primary application-level defenses.

Open term
DeFi

Flash Loan

An uncollateralized loan that must be borrowed and repaid within the same transaction. If the loan isn't repaid by transaction end, the entire transaction reverts atomically. Flash loans enable arbitrage, collateral swaps, and self-liquidation with zero capital. On Solana, Solend and MarginFi offer flash loans; they're also used in sandwich attacks.

Open term
Security

Duplicate Mutable Accounts

A vulnerability where the same account is passed twice in the accounts list for a single instruction under different argument names, and the program writes to what it believes are two independent accounts, with the second write silently overwriting the first on the single underlying account in the runtime's account map. For example, if from and to in a transfer handler reference the same key, debiting from and crediting to nets out to a free credit. In native programs the check requires comparing account keys; Anchor automatically detects duplicate mutable accounts and returns an error when the same pubkey appears more than once in writable positions within a single instruction's account list.

Open term
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Securityrevival-attack

Account Revival Attack

An exploit that resurrects an account that a program has logically closed within the same transaction by sending lamports back to it before the transaction finalizes, causing its on-chain data — which was never securely wiped — to re-appear as a funded, seemingly valid account in future transactions. Because the Solana runtime keeps an account alive as long as it holds any lamports, transferring even 1 lamport back to a closed-but-not-wiped account prevents its deletion and allows an attacker to reuse its stale state. The defense is to explicitly overwrite account data with a closed discriminator and to use force-defund patterns so any lamports transferred in during the same transaction are immediately drained.

Open term
Securityinstruction-ordering-attack

Instruction Ordering Attack

Exploit where an attacker crafts a transaction with instructions in a specific order to manipulate program state between instructions within the same transaction. Since Solana executes all instructions in a transaction sequentially, earlier instructions can modify account state that later instructions depend on, enabling unexpected state transitions.

Open term
Securitysandwich-attack

Sandwich Attack

A form of MEV where an attacker places one transaction immediately before (front-run) and one immediately after (back-run) a victim's large AMM swap: the front-run buys the asset first, driving up the price the victim pays, and the back-run sells the asset immediately after the victim's transaction at the inflated price, extracting the difference as profit. On Solana, sandwich attacks are facilitated through Jito bundles, which allow searchers to atomically guarantee ordering of multiple transactions within a block. Victims can mitigate exposure by setting tight slippage tolerances (e.g., 0.1–0.5%) and using DEX aggregators that route across multiple pools to reduce single-pool price impact.

Open term
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Securityoracle-manipulation

Oracle Manipulation

An attack in which an adversary artificially distorts the price or data reported by an on-chain oracle — most commonly by executing large trades to move a spot-price oracle (such as one based on a single AMM's instantaneous price) — and then exploits protocols that consume that price for lending, liquidation, or derivatives settlement before the oracle corrects. Flash-loan-amplified oracle manipulation is particularly dangerous: an attacker borrows a large sum atomically, moves the price, exploits the manipulated price, and repays the loan in one transaction. Defenses include using time-weighted average prices (TWAPs), aggregating multiple independent oracle sources (e.g., Pyth's aggregate confidence interval, Switchboard's weighted median), and enforcing staleness and confidence-band checks on every consumed price feed.

Open term
Securityfront-running

Front-Running

An attack where an adversary observes a pending or not-yet-finalized transaction (e.g., a large swap or NFT mint) and submits a competing transaction with higher priority fees or via validator relationships to execute before the victim's transaction, profiting from predictable price impact. On Solana, transactions are not held in a public mempool the same way as in Ethereum — leaders receive transactions privately — but front-running is still possible through Jito's block engine bundle mechanism, validator collusion, or by monitoring gossip. Slippage tolerance parameters and commit-reveal schemes are the primary application-level defenses.

Open term
DeFiflash-loan

Flash Loan

An uncollateralized loan that must be borrowed and repaid within the same transaction. If the loan isn't repaid by transaction end, the entire transaction reverts atomically. Flash loans enable arbitrage, collateral swaps, and self-liquidation with zero capital. On Solana, Solend and MarginFi offer flash loans; they're also used in sandwich attacks.

Open term
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Security

Missing Signer Check

A vulnerability where a program accepts an account in a privileged role (e.g., admin, authority, payer) without verifying that the account actually signed the transaction, allowing any caller to impersonate that authority by simply passing the target pubkey as an instruction account. In native Solana programs, the check requires asserting account.is_signer == true; in Anchor, the Signer<'info> type enforces this automatically. Exploitation lets an attacker bypass all access control gated on authority equality checks, making it one of the most critical and commonly audited vulnerabilities in Solana programs.

Open term
Security

Missing Owner Check

A vulnerability where a program deserializes and trusts account data without first confirming that the account is owned by the expected program, allowing an attacker to substitute a maliciously crafted account owned by a different program whose byte layout happens to satisfy the deserialization. On Solana, every account stores a 32-byte owner field set to the program that created it; native programs must assert account.owner == &expected_program_id, while Anchor's Account<'info, T> wrapper performs this check automatically. Failure to validate ownership can lead to complete auth bypass if an attacker can construct a fake account whose data parses into a struct with elevated privileges.

Open term
Security

Arbitrary CPI

A vulnerability where a program accepts an arbitrary program account from the caller and invokes it via Cross-Program Invocation (CPI) without verifying it matches a known, trusted program ID, effectively letting an attacker substitute a malicious program that executes under the victim program's authority or manipulates accounts the victim program passes to it. A common pattern is accepting a token_program account without checking it equals spl_token::ID, so the attacker passes a lookalike program that records or drains account data. Prevention requires hard-coding or explicitly checking the program ID before every CPI call.

Open term
Security

PDA Substitution Attack

A vulnerability where a program derives a PDA internally but accepts an externally supplied account as that PDA without re-deriving and comparing the address, allowing an attacker to pass a different PDA (derived from attacker-controlled seeds) that the program will treat as legitimate. Because PDAs are deterministic, the only way to guarantee account identity is to call Pubkey::find_program_address (or equivalent) with the expected seeds inside the program and assert the result equals the supplied key. Anchor's seeds and bump constraints on the Account type automate this re-derivation and equality check.

Open term