Vulnerability-Lookup

GHSA-R4HX-MHRP-XF73

Vulnerability from github – Published: 2026-07-17 12:31 – Updated: 2026-07-17 12:31

Details

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.

Severity

8.3 (High)


                  
                    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

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{
  "affected": [],
  "aliases": [
    "CVE-2026-59694"
  ],
  "database_specific": {
    "cwe_ids": [
      "CWE-1284"
    ],
    "github_reviewed": false,
    "github_reviewed_at": null,
    "nvd_published_at": "2026-07-17T11:17:13Z",
    "severity": "HIGH"
  },
  "details": "Improper Validation of Specified Quantity in Input in ZenHive mpp allows an unauthenticated remote client to inflate the fee-payer\u0027s gas cost per payment by a large multiplier, degrading the sponsor\u0027s operating margin.\n\nWhen 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.\n\nAt the maintainer\u0027s default of 137 access-list entries (fitting within Bandit\u0027s 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\u0027s operating margin on low-cost payments and, over time, drains the fee-payer wallet.\n\nThis issue affects mpp: from 0.2.0 before 0.6.0.",
  "id": "GHSA-r4hx-mhrp-xf73",
  "modified": "2026-07-17T12:31:29Z",
  "published": "2026-07-17T12:31:29Z",
  "references": [
    {
      "type": "WEB",
      "url": "https://github.com/ZenHive/mpp/security/advisories/GHSA-qpxh-ff8m-c62v"
    },
    {
      "type": "ADVISORY",
      "url": "https://nvd.nist.gov/vuln/detail/CVE-2026-59694"
    },
    {
      "type": "WEB",
      "url": "https://github.com/ZenHive/mpp/commit/5d6338e2334084c5f2a78cfcca474830733ed7e8"
    },
    {
      "type": "WEB",
      "url": "https://cna.erlef.org/cves/CVE-2026-59694.html"
    },
    {
      "type": "WEB",
      "url": "https://osv.dev/vulnerability/EEF-CVE-2026-59694"
    }
  ],
  "schema_version": "1.4.0",
  "severity": [
    {
      "score": "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/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X",
      "type": "CVSS_V4"
    }
  ]
}

CVE-2026-59694 (GCVE-0-2026-59694)

Vulnerability from cvelistv5 – Published: 2026-07-17 10:11 – Updated: 2026-07-17 12:22

Title

Unbounded access list in mpp Tempo fee-payer inflates gas cost per payment

Summary

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.

Severity

8.3 (High)


                        
                          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

SSVC

Exploitation: poc Automatable: no Technical Impact: partial

CISA Coordinator (v2.0.3)

CWE

CWE-1284 - Improper Validation of Specified Quantity in Input

Assigner

EEF

References

4 references

URL	Tags
https://github.com/ZenHive/mpp/security/advisorie…	vendor-advisoryrelated
https://cna.erlef.org/cves/CVE-2026-59694.html	related
https://osv.dev/vulnerability/EEF-CVE-2026-59694	related
https://github.com/ZenHive/mpp/commit/5d6338e2334…	patch

Impacted products

2 products

Vendor	Product	Version
ZenHive	mpp	Affected: 0.2.0 , < 0.6.0 (semver) cpe:2.3:a:ZenHive:mpp::::::::
ZenHive	mpp	Affected: d29d54e507918db00a5b65d90136b73166c017d7 , < 5d6338e2334084c5f2a78cfcca474830733ed7e8 (git) cpe:2.3:a:ZenHive:mpp::::::::

Credits

Kian Kai Ang E.FU Jonatan Männchen / EEF

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{
  "containers": {
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        "metrics": [
          {
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                "id": "CVE-2026-59694",
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                  },
                  {
                    "Technical Impact": "partial"
                  }
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                "role": "CISA Coordinator",
                "timestamp": "2026-07-17T12:22:40.105353Z",
                "version": "2.0.3"
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        "providerMetadata": {
          "dateUpdated": "2026-07-17T12:22:45.224Z",
          "orgId": "134c704f-9b21-4f2e-91b3-4a467353bcc0",
          "shortName": "CISA-ADP"
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            "url": "https://github.com/ZenHive/mpp/security/advisories/GHSA-qpxh-ff8m-c62v"
          }
        ],
        "title": "CISA ADP Vulnrichment"
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    ],
    "cna": {
      "affected": [
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          "collectionURL": "https://repo.hex.pm",
          "cpes": [
            "cpe:2.3:a:ZenHive:mpp:*:*:*:*:*:*:*:*"
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          "defaultStatus": "unaffected",
          "modules": [
            "\u0027Elixir.MPP.Tempo.Transaction\u0027"
          ],
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            "cpe:2.3:a:ZenHive:mpp:*:*:*:*:*:*:*:*"
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          "versions": [
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              "lessThan": "5d6338e2334084c5f2a78cfcca474830733ed7e8",
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              "versionType": "git"
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      ],
      "configurations": [
        {
          "lang": "en",
          "supportingMedia": [
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              "type": "text/html",
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            }
          ],
          "value": "The vulnerable code path is only reachable when the MPP.Methods.Tempo method is configured with fee_payer: true (server-side gas sponsorship). Default deployments with fee_payer: false are not affected, since the client pays for gas out of its own wallet."
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      "cpeApplicability": [
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              "operator": "AND"
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          "operator": "OR"
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      "credits": [
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          "type": "finder",
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          "type": "remediation developer",
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              "value": "\u003cp\u003eImproper Validation of Specified Quantity in Input in ZenHive mpp allows an unauthenticated remote client to inflate the fee-payer\u0027s gas cost per payment by a large multiplier, degrading the sponsor\u0027s operating margin.\u003c/p\u003e\u003cp\u003eWhen the \u003ctt\u003empp\u003c/tt\u003e Elixir library is configured as fee payer (\u003ctt\u003efee_payer: true\u003c/tt\u003e), \u003ctt\u003eMPP.Tempo.Transaction.cosign_fee_payer/3\u003c/tt\u003e re-signs the client-supplied base fields of the \u003ctt\u003e0x76\u003c/tt\u003e 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 \u003ctt\u003etransferWithMemo\u003c/tt\u003e 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.\u003c/p\u003e\u003cp\u003eAt the maintainer\u0027s default of 137 access-list entries (fitting within Bandit\u0027s 10,000-byte per-header-field limit) and 100 Gwei \u003ctt\u003emax_fee_per_gas\u003c/tt\u003e, per-payment gas cost rises from ~51,287 to ~380,087 gas, a 7.4x multiplier. Sustained abuse destroys the sponsor\u0027s operating margin on low-cost payments and, over time, drains the fee-payer wallet.\u003c/p\u003e\u003cp\u003eThis issue affects mpp: from 0.2.0 before 0.6.0.\u003c/p\u003e"
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      "impacts": [
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        },
        {
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          ],
          "url": "https://cna.erlef.org/cves/CVE-2026-59694.html"
        },
        {
          "tags": [
            "related"
          ],
          "url": "https://osv.dev/vulnerability/EEF-CVE-2026-59694"
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      "source": {
        "discovery": "EXTERNAL"
      },
      "title": "Unbounded access list in mpp Tempo fee-payer inflates gas cost per payment",
      "x_generator": {
        "engine": "cvelib 1.8.0"
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  "cveMetadata": {
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    "assignerShortName": "EEF",
    "cveId": "CVE-2026-59694",
    "datePublished": "2026-07-17T10:11:49.192Z",
    "dateReserved": "2026-07-06T14:05:47.003Z",
    "dateUpdated": "2026-07-17T12:22:45.224Z",
    "state": "PUBLISHED"
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}

Sightings

Author	Source	Type	Date	Other

Nomenclature

Seen: The vulnerability was mentioned, discussed, or observed by the user.
Confirmed: The vulnerability has been validated from an analyst's perspective.
Published Proof of Concept: A public proof of concept is available for this vulnerability.
Exploited: The vulnerability was observed as exploited by the user who reported the sighting.
Patched: The vulnerability was observed as successfully patched by the user who reported the sighting.
Not exploited: The vulnerability was not observed as exploited by the user who reported the sighting.
Not confirmed: The user expressed doubt about the validity of the vulnerability.
Not patched: The vulnerability was not observed as successfully patched by the user who reported the sighting.

Detection rules are retrieved from Rulezet.

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GHSA-R4HX-MHRP-XF73

CVE-2026-59694 (GCVE-0-2026-59694)

Tags

Sightings

Nomenclature