> 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/iop-paradex/46989-sc-insight-invalid-trade-side-check.md). # #46989 \[SC-Insight] Invalid trade side check **Submitted on Jun 7th 2025 at 11:54:53 UTC by @shaflow1 for** [**IOP | Paradex**](https://immunefi.com/audit-competition/iop-paradex) * **Report ID:** #46989 * **Report Type:** Smart Contract * **Report severity:** Insight * **Target:** * **Impacts:** ## Description ## Brief/Intro The `settle_trade_v2` function checks whether the `side` values in the orders are opposite, but this check may be invalid. Since the `side` in the orders can be any value, the direction is only considered positive when `side` equals 1, and negative for all other values. As a result, two different `side` values that are not equal to 1 can still pass the check, even though their actual trading directions are the same. ## Vulnerability Details ```rust #[derive(Copy, Drop, Serde, Debug, PartialEq)] pub struct OrderV2 { pub account: ContractAddress, pub market: felt252, pub side: felt252, pub orderType: felt252, pub size: felt252, pub price: felt252, pub signature_timestamp: felt252, pub is_reduce_only: bool, } fn settle_trade_v2(ref self: ContractState, trade: TradeRequestV2) -> felt252 { ... assert(trade.maker_order.side != trade.taker_order.side, Errors::TRADE_SAME_SIDE); ... } #[inline(always)] pub fn _get_sign_from_side(side: felt252) -> i128 { // Implement this function based on your side definitions if side == 1 { 1 } else { -1 } } ``` The OrderV2.side field can take any value, but only 1 is treated as the positive direction, while all other values are treated as the negative direction. The settle\_trade\_v2 function currently only checks whether the sides are unequal, which is insufficient. Instead, it should explicitly verify: 1. One side must be 1 2. The other side must be not 1 ## Impact Details Two orders with the same direction could be erroneously executed, leading to an imbalance between long and short positions in the system. ## References ## Proof of Concept ## Proof of Concept 1. There are two user orders with side values set to -1 and 2 respectively. 2. The executor calls settle\_trade\_v2 to process the orders. 3. Due to an ineffective trade side validation check, two short positions are opened instead of one short and one long position. --- # 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/iop-paradex/46989-sc-insight-invalid-trade-side-check.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.