CVE-2026-82751

Source
https://cve.org/CVERecord?id=CVE-2026-82751
Import Source
https://storage.googleapis.com/cve-osv-conversion/osv-output/CVE-2026-82751.json
JSON Data
https://api.osv.dev/v1/vulns/CVE-2026-82751
Aliases
Published
2026-09-06T16:07:26Z
Modified
2026-09-08T03:46:27Z
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 key authorization in mpp Tempo fee-payer sponsorship inflates gas cost and sponsors access-key provisioning
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 sponsored payment by a large multiplier and to have the sponsor pay for provisioning an access key on the client's own account.

When the server sponsors Tempo payments, MPP.Methods.Tempo.FeePayerPolicy.measure/3 in lib/mpp/methods/tempo/fee_payer_policy.ex bounds the gas fields, the fee budget, the validity window and the access list of the client-signed 0x76 envelope, but does not check whether the envelope carries the optional key_authorization field. A client can attach a fully signed key authorization, provisioning a new access key with token spending limits on its own account, alongside the normal payment call. The key and each limit entry are persistent storage writes billed as intrinsic gas to the sponsor, bounded only by the gas_limit ceiling. At the reporter's default of one key with three token limits the sponsored cost rises from about 46,587 gas to about 1,808,700 gas, and the client keeps a valid access key it paid nothing for.

This issue affects mpp: from 0.2.0 before 0.16.1.

Database specific
{
    "cna_assigner": "EEF",
    "cwe_ids": [
        "CWE-1284"
    ],
    "osv_generated_from": "https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/82xxx/CVE-2026-82751.json",
    "unresolved_ranges": [
        {
            "extracted_events": [
                {
                    "introduced": "0.2.0"
                },
                {
                    "fixed": "0.16.1"
                },
                {
                    "introduced": "d29d54e507918db00a5b65d90136b73166c017d7"
                },
                {
                    "fixed": "0482572b47e1ffe1537ab80ab613d47b92833c2d"
                }
            ],
            "source": "AFFECTED_FIELD"
        },
        {
            "extracted_events": [
                {
                    "introduced": "0.2.0"
                },
                {
                    "fixed": "0.16.1"
                }
            ],
            "source": "CPE_FIELD"
        },
        {
            "extracted_events": [
                {
                    "introduced": "0.2.0"
                },
                {
                    "fixed": "0.16.1"
                }
            ],
            "source": "DESCRIPTION"
        }
    ]
}
References

Affected packages

Git / github.com/zenhive/mpp

Affected ranges

Type
GIT
Repo
https://github.com/zenhive/mpp
Events
Introduced
0 Unknown introduced commit / All previous commits are affected
Fixed
Database specific
Show details
{
    "source": "REFERENCES"
}

Affected versions

v0.*
v0.1.0
v0.10.0
v0.11.0
v0.12.0
v0.13.0
v0.14.0
v0.15.0
v0.16.0
v0.2.0
v0.3.0
v0.4.0
v0.5.1
v0.6.0
v0.6.1
v0.6.3
v0.6.4
v0.7.0
v0.8.0
v0.9.0

Database specific

source
"https://storage.googleapis.com/cve-osv-conversion/osv-output/CVE-2026-82751.json"