CVE-2026-59694

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Source
https://cve.org/CVERecord?id=CVE-2026-59694
Import Source
https://storage.googleapis.com/cve-osv-conversion/osv-output/CVE-2026-59694.json
JSON Data
https://api.osv.dev/v1/vulns/CVE-2026-59694
Aliases
Published
2026-07-17T10:11:49.192Z
Modified
2026-08-12T03:51:09.722686821Z
Severity
  • 8.3 (High) CVSS_V4 - 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 CVSS Calculator
Summary
Unbounded access list in mpp Tempo fee-payer inflates gas cost per payment
Details

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 (feepayer: true), MPP.Tempo.Transaction.cosignfee_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 maxfeeper_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.

Database specific 
{
    "osv_generated_from": "https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/59xxx/CVE-2026-59694.json",
    "unresolved_ranges": [
        {
            "source": "AFFECTED_FIELD",
            "extracted_events": [
                {
                    "introduced": "d29d54e507918db00a5b65d90136b73166c017d7"
                },
                {
                    "fixed": "5d6338e2334084c5f2a78cfcca474830733ed7e8"
                }
            ]
        }
    ],
    "cwe_ids": [
        "CWE-1284"
    ],
    "cna_assigner": "EEF"
}
References

Affected packages

Git / github.com/zenhive/mpp

Affected ranges

Type
GIT
Repo
https://github.com/zenhive/mpp
Events
Introduced
7ca7538f05959a98e0e5e63e4bd949b4f362cf8d
Fixed
422bcdd066d1457a93bf5e75fd55e71c5e0be961
Fixed
5d6338e2334084c5f2a78cfcca474830733ed7e8
Database specific
Show details 
{
    "source": [
        "DESCRIPTION",
        "REFERENCES"
    ],
    "extracted_events": [
        {
            "introduced": "0.2.0"
        },
        {
            "fixed": "0.6.0"
        }
    ]
}

Affected versions

v0.*
v0.2.0
v0.3.0
v0.4.0
v0.5.1

Database specific

source 
"https://storage.googleapis.com/cve-osv-conversion/osv-output/CVE-2026-59694.json"