CyberRota Analysis
AI-GeneratedThe ZenHive mpp library is vulnerable due to improper validation of input in the transaction cosigning process, allowing unauthenticated remote clients to inflate gas costs significantly for fee-payers. This exploitation can lead to a dramatic increase in transaction fees—up to 7.4 times the expected amount—resulting in substantial financial losses for sponsors and draining the fee-payer's wallet over time. Organizations using affected versions of the mpp library (0.2.0 to 0.6.0) should prioritize addressing this vulnerability to mitigate potential operational impacts.
Public Exploit Signal
A public exploit, PoC, GitHub repository or Metasploit reference was detected for this CVE.
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Original NVD Description
Improper Validation of Specified Quantity in Input in ZenHive mpp allows an unauthenticated remote client to inflate the fee-payer's gas cost per payment by a large multiplier, degrading the sponsor's operating margin. When the mpp Elixir library is configured as fee payer (fee_payer: true), MPP.Tempo.Transaction.cosign_fee_payer/3 re-signs the client-supplied base fields of the 0x76 AASigned envelope verbatim, including the EIP-2930 access list, without validating its length or contents. EIP-2930 access list entries incur intrinsic gas (~2,400 gas per address, plus 1,900 gas per storage key) charged before any opcode executes, regardless of whether the listed addresses are ever touched. A malicious client submits a valid transferWithMemo call alongside a large number of fabricated access-list entries. The server co-signs and broadcasts the transaction. The intended transfer executes normally, but the fee-payer wallet pays a large multiple of the expected gas cost with no corresponding on-chain work. At the maintainer's default of 137 access-list entries (fitting within Bandit's 10,000-byte per-header-field limit) and 100 Gwei max_fee_per_gas, per-payment gas cost rises from ~51,287 to ~380,087 gas, a 7.4x multiplier. Sustained abuse destroys the sponsor's operating margin on low-cost payments and, over time, drains the fee-payer wallet. This issue affects mpp: from 0.2.0 before 0.6.0.