Aragon — EarlyExecution proposals vulnerable to flashloan vote attacks

Source & credit. Reproduction of a public audit finding curated by AuditVault — the original finding: 62256-proposals-created-with-voting-mode-earlyexecution-are-vulner. Standalone Foundry PoC and full write-up: 62256-proposals-created-with-voting-mode-earlyexecution-are-vulner_exp in the evm-hack-registry mirror.

Vulnerability classes: vuln/governance/flashloan-vote · trigger/flash-loan · impact/unauthorized-execution

Reproduction: a self-contained Foundry PoC that compiles & runs in an isolated project with only forge-std — no fork, no RPC, no anvil_state. Full trace: output.txt. PoC: test/62256-proposals-created-with-voting-mode-earlyexecution-are-vulner_exp.sol.

Key info#

TL;DR#

1. EarlyExecution mode executes a proposal as soon as a YES vote pushes it over the support threshold.
2. If the lock token is flashloanable/flashmintable, an attacker can temporarily lock enough weight to cast that YES vote.
3. Inside the same transaction they unlock and repay the flashloan — no lasting stake.
4. The proposal action runs (here: drain a 5 REWARD treasury pot to the flash voter).
5. HARM: unauthorized early execution + treasury payout with zero lasting lock.

The vulnerable code#

function _vote(...) internal {
    // tally YES/NO ...
    if (p.mode == VotingMode.EarlyExecution && _hasSucceeded(p)) {
        _execute(proposalId); // @> VULN: same-tx early execute after flashloaned YES
        // FIX: delay execute to a later block, or remove EarlyExecution (Aragon PR 26)
    }
}

Attack shape (finding PoC):

flashloan → lock → lockAndVote(YES) → early execute → unlock → repay

Root cause#

Early execution binds “proposal succeeded” to “execute now” without requiring economic finality of the voting weight. Ephemeral flashloaned weight is enough.

Preconditions#

• Proposal created with VotingMode.EarlyExecution.
• Lock token can be flashloaned or flashminted.
• Attacker can reach the support / min-participation thresholds with temporary weight.

Attack walkthrough#

1. Create EarlyExecution proposal: treasury.payout(voter, 5 ether).
2. Flashmint 10 lock tokens to the FlashVoter.
3. lockAndVote(YES, 10e18) — threshold met → _execute runs.
4. Unlock and repay the flashmint.
5. Voter holds 5 REWARD; treasury is empty; locked balance is 0.

Diagrams#

Impact#

• Any EarlyExecution proposal can be force-executed without lasting voter capital.
• DAO actions (transfers, permission grants, upgrades) become flashloan-triggerable.
• Aragon removed EarlyExecution rather than add a same-block delay.

Sources#

• AuditVault finding #62256
• Spearbit Aragon July 2025 report
• Fixed in Aragon PR 26 (EarlyExecution removed)

Taxonomy (AuditVault)#

• severity/high · sector/governance · platform/spearbit · trigger/flash-loan
• genome: flash-loan-attack · role-bypass · flashloan-callback-auth · proposal-state-check

Sources & further analysis#

Reproductions & code

• Standalone PoC + full trace: 62256-proposals-created-with-voting-mode-earlyexecution-are-vulner_exp (evm-hack-registry mirror).
• AuditVault finding: 62256-proposals-created-with-voting-mode-earlyexecution-are-vulner.

Alerts & third-party analyses

• Web3Sec X hacked database: search.
• Rekt leaderboard: search.
• Solodit incident search: search.

These dashboards index community alerts tweets, post-mortems, and independent write-ups. Reach them through the protocol name above to cross-check this reproduction against other analyses.