> For the complete documentation index, see [llms.txt](https://reports.immunefi.com/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://reports.immunefi.com/alchemix/31485-sc-critical-miscalculation-of-distributed-tokens-at-revenue....md). # 31485 - \[SC - Critical] Miscalculation of distributed tokens at revenue... Submitted on May 20th 2024 at 06:40:34 UTC by @MahdiKarimi for [Boost | Alchemix](https://immunefi.com/bounty/alchemix-boost/) Report ID: #31485 Report type: Smart Contract Report severity: Critical Target: Impacts: * Theft of unclaimed yield ## Description ## Brief/Intro Revenue handler uses contract balance to calculate distribution amount, so if users didn't claim their rewards from the last distribution, unclaimed amount is mistakenly considered as newly distributed rewards ## Vulnerability Details Every time the checkpoint is called at revenue handler to distribute revenues, it uses the contract balance as the amount to be distributed. However, if some users haven't claimed their rewards from previous distributions, those unclaimed rewards are mistakenly considered as newly distributed rewards so some users can receive more rewards while others can't receive their rewards. ## Impact Details Inconsistency between contract balance and user claimable amount enables some users to receive more rewards while some users are not able to receive any rewards ## References ## Proof of Concept ``` function testClaimAfterNextCheckpoint() external { uint256 revAmt = 1000e18; uint256 tokenId = _setupClaimableNonAlchemicRevenue(revAmt, bal); uint256 tokenId2 = _setupClaimableNonAlchemicRevenue(revAmt, bal); uint256 claimable = revenueHandler.claimable(tokenId, bal); uint256 claimable2 = revenueHandler.claimable(tokenId2, bal); // as we see contract balance is not sufficient for claimable amount assert(claimable > IERC20(bal).balanceOf(address(revenueHandler))); assert(claimable + claimable2 > IERC20(bal).balanceOf(address(revenueHandler))); } ``` --- # Agent Instructions This documentation is published with GitBook. GitBook is the documentation platform designed so that both humans and AI agents can read, navigate, and reason over technical content effectively. Learn more at gitbook.com. ## Querying This Documentation If you need additional information that is not directly available in this page, you can query the documentation by asking a question. Perform an HTTP GET request on the following URL with the `ask` and `goal` query parameters: ``` GET https://reports.immunefi.com/alchemix/31485-sc-critical-miscalculation-of-distributed-tokens-at-revenue....md?ask=&goal= ``` `ask` is the immediate question: it should be specific, self-contained, and written in natural language. `goal` is what the user is ultimately trying to achieve, the reason they need the answer. Sharing it helps GitBook give you a better, more relevant answer. A goal is most helpful when it describes the outcome the user wants rather than restating the question. For example, with `ask=how do I create an API token`, a goal like `automate deployments from our CI pipeline` lets GitBook tailor the answer to that use case. The response will contain a direct answer to the question and relevant excerpts and sources from the documentation. Use this mechanism when the answer is not explicitly present in the current page, you need clarification or additional context, or you want to retrieve related documentation sections.