CVE-2026-54754 in Klever-Go
Summary
by MITRE • 08/28/2026
Klever-Go is the Go implementation of the Klever blockchain protocol. Prior to 1.7.19, marketplace settlement in core/kapp/market/market.go reads MarketOrderData.ReferralPercentage from the listing while reading asset.Royalties.MarketPercentage live at purchase time. An asset owner can create a valid listing and then use AssetTrigger UpdateRoyalties to make the combined referral and royalty percentages exceed the bid. executeBuyMarket pays referral and royalty amounts unconditionally while computeMarketOwnerAmount silently skips a nonpositive seller remainder, allowing MarketBuy, BuyItNow, or auction Claim settlement to credit more KLV or sale currency than the buyer paid. This can create unbacked currency and corrupt token supply integrity. This issue is fixed in version 1.7.19.
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Analysis
by VulDB Data Team • 08/28/2026
The Klever-Go blockchain protocol implementation contains a critical logic vulnerability within its marketplace settlement mechanism that allows for the creation of unbacked cryptocurrency, thereby compromising the integrity of the total token supply. Prior to version 1.7.19, the core module responsible for handling market transactions exhibits a flaw in how it calculates and distributes payments between asset owners, referral agents, and the platform itself during the execution of buy orders or auction claims. This vulnerability stems from an inconsistency in reading configuration data at different stages of the transaction lifecycle, specifically involving the interaction between listing parameters and dynamic royalty settings.
The technical root cause lies in a discrepancy between static and dynamic data retrieval within the market.go module. When a seller creates a valid marketplace listing, they specify a referral percentage which is stored as part of the MarketOrderData structure. However, when a buyer executes this order via functions such as executeBuyMarket or related settlement methods like BuyItNow or auction Claim processing, the system does not re-read the current state of these percentages from the persistent storage at that exact moment. Instead, it relies on the static referral percentage defined in the original listing while simultaneously fetching the asset royalties dynamically from AssetTrigger UpdateRoyalties live at purchase time. This decoupling allows an asset owner to manipulate the financial outcome by altering royalty settings after a sale is initiated but before or during its settlement phase.
An attacker can exploit this flaw by first creating a standard marketplace listing with specific referral and royalty parameters that appear valid under normal circumstances. Subsequently, using the AssetTrigger UpdateRoyalties function available to the asset owner, they modify the royalties associated with the asset such that the sum of the new royalty percentage and the original static referral percentage exceeds the total bid price or sale value agreed upon by the buyer. Because the executeBuyMarket function unconditionally pays out both the referral amount and the royalty amount without validating whether their combined total surpasses the incoming payment, the system proceeds to distribute funds based on these inflated percentages.
The operational impact of this vulnerability is severe due to a secondary logic error in the computation of seller proceeds. The computeMarketOwnerAmount function, which determines the net amount payable to the asset owner after deductions for royalties and referrals, contains a flaw where it silently skips or ignores cases resulting in a non-positive remainder for the seller. In standard financial systems, if deductions exceed revenue, the transaction should either fail entirely or result in negative balances that are handled explicitly. Here, however, the system allows the referral and royalty payouts to proceed even when they consume more than the buyer paid. Consequently, the smart contract mints additional KLV tokens or sale currency out of thin air to cover these excess payments, effectively creating unbacked currency. This leads to inflationary pressure on the Klever token supply and corrupts the fundamental economic model by allowing value creation without corresponding asset transfer or liquidity provision.
This vulnerability aligns with CWE-20 Improper Input Validation as it involves a failure to properly validate that financial deductions do not exceed available funds before executing transfers. Furthermore, from an offensive security perspective, this represents a classic logic flaw often categorized under ATT&CK techniques related to resource manipulation and economic exploitation within decentralized applications. The attack does not require compromising private keys or exploiting cryptographic weaknesses but rather leverages the application's own business logic rules against itself through temporal manipulation of state variables.
The issue has been addressed in Klever-Go version 1.7.19, which corrects the settlement logic to ensure that all percentage calculations are performed consistently and validated against available funds before any distribution occurs. To mitigate similar risks in other implementations or during the transition period, developers should enforce strict validation checks at the point of transaction execution rather than relying on cached listing data. It is essential to recalculate total deductions using current state variables for both royalties and referrals simultaneously, ensuring that their sum never exceeds the bid amount. Additionally, implementing explicit failure conditions when seller remainders are non-positive will prevent silent skipping logic from masking overpayments. Regular audits of financial smart contracts focusing on edge cases in percentage-based distributions are recommended to maintain supply integrity and trust within decentralized marketplaces.