---
cve: "CVE-2026-59694"
severity: "HIGH"
cvss: 8.3
epss: "30%"
vendor: "ZenHive"
kev: false
exploited: false
published: "2026-07-17 11:17:13"
tags: [cve, security, high]
source: tsecurity.de CVE-Dossier
exported: "2026-09-14T18:44:40+02:00"
---

# CVE-2026-59694

> 8.3 HIGH · 🧪 PoC

## Beschreibung

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-Vektor

```
CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:N/VC:N/VI:H/VA:L/SC:N/SI:N/SA:N
```

| Metrik | Wert | Bewertung |
|---|---|---|
| AV Angriffsvektor | Netzwerk | bad |
| AC Komplexität | Gering | bad |
| PR Privilegien | Keine | bad |
| UI Interaktion | Keine | bad |

## Patch verfügbar (OSV)

- 422bcdd066d1457a93bf5e75fd55e71c5e0be961 (Commit)
- 5d6338e2334084c5f2a78cfcca474830733ed7e8 (Commit)

## Referenzen

- <https://github.com/ZenHive/mpp/security/advisories/GHSA-qpxh-ff8m-c62v>
- <https://cna.erlef.org/cves/CVE-2026-59694.html>
- <https://osv.dev/vulnerability/EEF-CVE-2026-59694>
- <https://github.com/ZenHive/mpp/commit/5d6338e2334084c5f2a78cfcca474830733ed7e8>

---
_Exportiert aus dem [tsecurity.de CVE-Dossier](https://tsecurity.de/cve?cve=CVE-2026-59694) · Datenquellen: EUVD (ENISA), NVD, OSV, CISA KEV, FIRST EPSS, Exploit-DB, BSI BITS_