YuzuUSD: A withdrawer who opens a redeem order is paid the fixed pre-yield amount (100e18) at final

Source & credit. Reproduction of a public audit finding curated by AuditVault — the original finding: 62756-h-01-pending-withdrawals-in-yuzuilp-contract-are-not-conside. The historical source/toolchain is unavailable; this entry is documentation only and claims no executable Forge PoC.

Vulnerability classes: vuln/logic

Reproduction: a faithful minimal reproduction of the vulnerable finding — the vulnerable function is reproduced verbatim (marked @>) with faithful minimal doubles; local deploy, no fork.

Root cause#

A withdrawer who opens a redeem order is paid the fixed pre-yield amount (100e18) at finalize, while their still-counted shares earned 50e18 of yield during the pending window; that 50e18 leaks to the remaining holder (B's redeemable rises 150e18->200e18), so the withdrawer loses their rightful pro-rata yield.

SOLIDITY

            revert ExceededMaxRedeemOrder(owner, tokens, maxTokens);
        }

        uint256 assets = previewRedeemOrder(tokens); // @> asset value FIXED at current pre-yield price; the redeemed shares are NOT excluded from totalAssets()/totalSupply(), so they keep accruing yield the withdrawer never receives
        address caller = _msgSender();
        uint256 orderId = _createRedeemOrder(caller, receiver, owner, tokens, assets);

Why it's exploitable here#

Attack path#

flowchart TD S0["Total assets from balance"] S1["Preview deposit shares"] S2["Convert shares to assets"] S3["Open a redeem order"] S4["Lock payout before yield accrues"] H["A withdrawer who opens a redeem order is paid the fixed pre-yield amou"] S0 --> S1 S1 --> S2 S2 --> S3 S3 --> S4 S4 --> H

Marked-line walkthrough (Playground)#

The EVM Playground pins each step to the exact executed source line in 0x671d353a77…:

L106 — Total assets from balance: Total assets equal the vault's live asset balance, which grows as yield accrues over time.
L123 — Preview deposit shares: Setup: view converting a deposit amount into the shares it would mint.
L128 — Convert shares to assets: Converts a share amount into assets at the vault's current pool ratio.
L145 — Open a redeem order: Entry point where a holder queues a redeem order to be finalized later, opening a pending window.
L158 — Lock payout before yield accrues: Root cause: freezes the payout at the current pre-yield value; the escrowed shares keep earning yield during the pending window that the withdrawer never receives.
L160 — Store order with frozen amount: Records the order with that frozen assets figure, so finalize later pays only the stale pre-yield amount.
L176 — Debit owner's shares to escrow: Debits the redeeming shares from the owner as the order is escrowed, yet they stay counted and keep accruing yield that leaks to remaining holders.

PoC#

Registry (Foundry, local deploy — verbatim vulnerable source + harm-asserting test + negative control):

BASH

cd 62756-h-01-pending-withdrawals-in-yuzuilp-contract-are-not-conside_exp
forge test -vvv

The browser Playground replays the same synthetic opcode-for-opcode and measures the harm: A withdrawer who opens a redeem order is paid the fixed pre-yield amount (100e18) at finalize, while their still-counted shares earned 50e18. Both gates are green (registry forge test PASS + Playground _verify-poc VERDICT: PASS).

Sources & further analysis#

Reproductions & code

No executable Forge reproduction is claimed; the historical source/toolchain was unavailable for this finding.
AuditVault finding: 62756-h-01-pending-withdrawals-in-yuzuilp-contract-are-not-conside.
Upstream DeFiHackLabs PoC directory: src/test.

Alerts & third-party analyses

DeFiHackLabs incident explorer: search "YuzuUSD: A withdrawer who opens a redeem order is paid the fixed pre-yield amount (100e18) at final".
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.

Source-level debugger — step opcodes and Solidity in sync