# 59168 sc low incorrect time semantics in periodattimestamp cause off chain miscalculations and data inconsistency **Submitted on Nov 9th 2025 at 14:33:19 UTC by @Arkindyo for** [**Audit Comp | Firelight**](https://immunefi.com/audit-competition/audit-comp-firelight) * **Report ID:** #59168 * **Report Type:** Smart Contract * **Report severity:** Low * **Target:** * **Impacts:** * Griefing (e.g. no profit motive for an attacker, but damage to the users or the protocol) ## Description ## Brief/Intro The `periodAtTimestamp(uint48 timestamp)` function in `FirelightVault.sol` returns the current period number based on the current block timestamp, not the period for the provided `timestamp`. \##Vulnerability Details The `periodAtTimestamp` function is documented to return “the period number for the given timestamp”, but it computes with `Time.timestamp()` (current block time) instead of the provided `timestamp`. Although it correctly selects the period configuration applicable to the provided `timestamp` via `periodConfigurationAtTimestamp(timestamp)`, the quotient uses the elapsed time since `epoch` based on “now” rather than the provided `timestamp`. [firelight-core/contracts/FirelightVault.sol::periodAtTimestamp#249](https://github.com/firelight-protocol/firelight-core/blob/db36312f1fb24efc88c3fde15a760defbc3e6370/contracts/FirelightVault.sol#L249) [firelight-core/contracts/FirelightVault.sol::\_sinceEpoch#796](https://github.com/firelight-protocol/firelight-core/blob/db36312f1fb24efc88c3fde15a760defbc3e6370/contracts/FirelightVault.sol#L796) ```solidity function periodAtTimestamp(uint48 timestamp) public view returns (uint256) { PeriodConfiguration memory periodConfiguration = periodConfigurationAtTimestamp(timestamp); // solhint-disable-next-line max-line-length return periodConfiguration.startingPeriod + _sinceEpoch(periodConfiguration.epoch) / periodConfiguration.duration; } function _sinceEpoch(uint48 epoch) private view returns (uint48) { return Time.timestamp() - epoch; } ``` ## Impact Details * Incorrect historical/future queries: Any off-chain analytics, dashboards, or integrators using `periodAtTimestamp(pastOrFutureTs)` will receive the period number for “now” (under the configuration that would apply to `timestamp`), not for the actual `timestamp`. * Mis-scheduling and mislabeling: Systems that plan actions or label data by period number may misassign entries, leading to misleading reports and operational errors (e.g., wrong “batch” attribution or period-based KPIs). * User confusion and governance optics: Period-based histories and charts may appear inconsistent, undermining trust and complicating audits. ## Recommended Fix Update the computation to use the provided `timestamp`: ```solidity function periodAtTimestamp(uint48 timestamp) public view returns (uint256) { PeriodConfiguration memory periodConfiguration = periodConfigurationAtTimestamp(timestamp); // solhint-disable-next-line max-line-length - return periodConfiguration.startingPeriod + _sinceEpoch(periodConfiguration.epoch) / periodConfiguration.duration; + return periodConfiguration.startingPeriod + (timestamp - periodConfiguration.epoch) / periodConfiguration.duration; } ``` * The contract enforces left-closed, right-open intervals for period divisions. With the correct formula, when `timestamp == pc.epoch + k * pc.duration`, the function should return `pc.startingPeriod + k`. * Period alignment and configuration transitions are already guarded by `_addPeriodConfiguration` and `periodConfigurationAtTimestamp`, so using `(timestamp - pc.epoch)` is safe (no underflow) because `timestamp >= pc.epoch` for the selected configuration. ## References Code: `firelight-core/contracts/FirelightVault.sol`, `periodAtTimestamp(uint48 timestamp)` and `_sinceEpoch(uint48 epoch)`. [firelight-core/contracts/FirelightVault.sol::periodAtTimestamp#249](https://github.com/firelight-protocol/firelight-core/blob/db36312f1fb24efc88c3fde15a760defbc3e6370/contracts/FirelightVault.sol#L249) [firelight-core/contracts/FirelightVault.sol::\_sinceEpoch#796](https://github.com/firelight-protocol/firelight-core/blob/db36312f1fb24efc88c3fde15a760defbc3e6370/contracts/FirelightVault.sol#L796) ## Proof of Concept ## Proof of Concept The `periodAtTimestamp` function uses the current block time instead of the input timestamp, causing incorrect period numbers when querying past or future timestamps. This test `test_PeriodAtTimestamp_UsesNowInsteadOfArg()` publicconstructs a period configuration that has already started in the past, then queries with a "past timestamp" to assert that the returned value equals the period based on the `current` time rather than the correct one based on the query timestamp. ```bash Ran 1 test for contracts/test/FirelightVaultUpgradeTest.sol:FirelightVaultUpgradeTest [PASS] test_PeriodAtTimestamp_UsesNowInsteadOfArg() (gas: 54414) Suite result: ok. 1 passed; 0 failed; 0 skipped; finished in 2.17ms (201.97µs CPU time) ``` ```solidity /* SPDX-License-Identifier: UNLICENSED */ pragma solidity 0.8.28; import {FirelightVault} from "../FirelightVault.sol"; import {Checkpoints} from "../lib/Checkpoints.sol"; import {SafeERC20} from "@openzeppelin/contracts/token/ERC20/utils/SafeERC20.sol"; import {IERC20} from "@openzeppelin/contracts/token/ERC20/IERC20.sol"; import {Test} from "../../lib/forge-std/src/Test.sol"; contract FirelightVaultUpgradeTest is FirelightVault, Test { using Checkpoints for Checkpoints.Trace256; using SafeERC20 for IERC20; function updateVersion(uint256 version) public { contractVersion = version; } // POC: test_PeriodAtTimestamp_UsesNowInsteadOfArg function test_PeriodAtTimestamp_UsesNowInsteadOfArg() public { uint48 epoch0 = uint48(block.timestamp); PeriodConfiguration memory pc = PeriodConfiguration({ epoch: epoch0, duration: uint48(100), startingPeriod: 0 }); periodConfigurations.push(pc); uint48 queryTs = epoch0 + 1; uint256 expectedCorrect = pc.startingPeriod + (uint256(queryTs) - uint256(pc.epoch)) / uint256(pc.duration); vm.warp(uint256(epoch0) + 150); uint256 nowBased = pc.startingPeriod + (uint256(uint48(block.timestamp)) - uint256(pc.epoch)) / uint256(pc.duration); uint256 actual = periodAtTimestamp(queryTs); require( actual == nowBased, "periodAtTimestamp returns now-based period instead of ts-based" ); require( actual != expectedCorrect, "periodAtTimestamp should not equal correct period for past ts" ); } } ``` --- # Agent Instructions: Querying This Documentation If you need additional information that is not directly available in this page, you can query the documentation dynamically by asking a question. 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