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.
CVSS
No CVSS.
References
Configurations
No configuration.
History
17 Jul 2026, 13:18
| Type | Values Removed | Values Added |
|---|---|---|
| References | () https://github.com/ZenHive/mpp/security/advisories/GHSA-qpxh-ff8m-c62v - |
17 Jul 2026, 11:17
| Type | Values Removed | Values Added |
|---|---|---|
| New CVE |
Information
Published : 2026-07-17 11:17
Updated : 2026-07-17 18:09
NVD link : CVE-2026-59694
Mitre link : CVE-2026-59694
CVE.ORG link : CVE-2026-59694
JSON object : View
Products Affected
No product.
CWE
CWE-1284
Improper Validation of Specified Quantity in Input