audit(sPRL2V2): Bailsec June 2026 remediation (Bailsec-02/03/05/06)

[FabienCoutant]

Overview

Audit remediation for sPRL2V2 following the Bailsec sPRLV2 1st report (June 2026). Targets feat/sprl2v2.

Report: docs/audits/Bailsec - Parallel - sPRL2V2 - 1st Report - June 2026.pdf

Findings: 0 High · 2 Medium · 5 Low · 9 Informational. The four findings below are fixed; the remainder are acknowledged (see table).

Audit remediation

Code changes addressing the report's findings:

• [Issue_02] Duplicate symbol during migration (Medium) — both sPRL2 and sPRL2V2 exposed the same sPRL2 symbol while both tokens are live during the migration window, risking conflation by any symbol-keyed consumer (explorers, the reward-merkle distributor's off-chain eligibility input). The SYMBOL constant is now sPRL2V2. NAME already differed from the legacy ...Aura Deposit Vault, so it is left untouched.
• [Issue_03] Extra rewards cannot be withdrawn (Medium) — reward tokens routed to the contract on its behalf (e.g. MERKL onBehalf distributions) would be permanently locked. Adds a restricted recoverERC20(token) that forwards the full balance to feeReceiver. The guard reverts with CannotRecoverUnderlying() when token == underlying, so the share-backing asset (BPT for sPRL2V2, PRL for sPRL1) can never be drained. Placed in the shared TimeLockPenaltyERC20 base keyed on underlying rather than a contract-specific BPT check, so every derived staking token benefits.
• [Issue_05] requestWithdraw can be invoked with zero amount (Low) — requestWithdraw(0) minted an empty, cancellable request occupying a request ID. Now reverts with NullAmount(). Guard added to the shared base.
• [Issue_06] feeReceiver coupled exits can produce failure states (Low) — an address(0) feeReceiver would revert the slash transfer in every premature exit, DoS-ing all early withdrawals. Adds a zero-address guard (FeeReceiverZeroAddress()) in both the base constructor and updateFeeReceiver.

Acknowledged (no code change)

ID	Sev	Title	Rationale
Issue_01	Low	Shared nonce (permit / delegateBySig)	Inherent to OZ ERC20Votes + ERC20Permit; recoverable, no fund loss. Document for users.
Issue_04	Low	Missing native ETH exit	Users unwrap WETH→ETH themselves; keeps the contract surface minimal.
Issue_07	Low	Min amounts calibrated on post-fee amount	Slippage params are the user's responsibility; documentation note.
Issue_08	Info	Balancer V3 minimum trade amount on exit	Atomic revert, no state corruption.
Issue_09	Info	Pending sPRL2 requests bypass waiting period	Expected during the paused migration; note only.
Issue_10	Info	balanceOf manipulable via request/cancel	No governance logic relies on raw balanceOf.
Issue_11	Info	Voting power denomination fluctuates	Inherent to BPT-backed VP; note only.
Issue_12	Info	Address-derived isReversedBalancerPair	Current mainnet deployment order matches; slippage params guard.
Issue_13	Info	findUnlockingIDs empty array on start-from-end	Off-chain helper only; callers use _startFromEnd=false.
Issue_14	Info	uint160 cast truncation	Supply never reaches 2^160; consistency note.
Issue_15	Info	Theoretical uint208 supply cap	Atomic revert; no corruption.
Issue_16	Info	Migrated deposits attributed to migrator in event	Cosmetic; document the migration flow.

Tests

• New: recoverERC20 (recover to feeReceiver, revert on underlying, revert on unauthorized) in the timeLockPenaltyERC20 suite (matching the base contract).
• New: zero-amount requestWithdraw revert, zero-address feeReceiver revert (constructor + updateFeeReceiver), updated symbol assertion.
• Full CI suite green locally (lint + forge build --sizes + forge test): 188 passed, 0 failed (fuzz 1000 runs, forks included). sPRL2V2 runtime size 21,423 < 24,576.

Note

PR intended for audit review — do not merge until the audit is finalized.