TI-2026-57069 Aliases CVE-2026-82751 GHSA-6fjm-7mv9-c325

Unbounded key authorization in mpp Tempo fee-payer sponsorship inflates gas cost and sponsors access-key provisioning

LOW 37CWE-1284Published 2026-09-06 · Updated 2026-09-08

Key facts

Attack vector: Network
Privileges required: None
User interaction: None
Attack complexity: Low
Attack requirements: Present
Impact type: —
Confidentiality · integrity · availability: None · High · Low
Fix status: Fixed

Attack profile from CVSS 4.0 · CNA. Fix status from CNA.

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 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.

Why it matters now

Exploitation None reported CISA SSVC · not in CISA KEV

EPSS 0.00524 44th percentileScored 2026-11-07

Fix Fixed mpp (ZenHive): 0.16.1

SSVC decision points

CISA ADP · SSVC 2.0.3

Exploitation: None
Automatable: No
Technical impact: Partial

The decision (Track, Attend, Act) also depends on your mission and well-being impact; see CISA's SSVC guide.

Affected products

Vendor	Product	Affected versions	Fixed in	Status	Source
ZenHive	mpp	0.2.0 to before 0.16.1	0.16.1	Patch available	CNA

mpp VendorZenHive Affected 0.2.0 to before 0.16.1 Fixed in 0.16.1 Patch available CNA

CPE names CNA · 1

CPE	Versions	Role	Vendor
cpe:2.3:a:ZenHive:mpp::::::::	—	—	—

cpe:2.3:a:ZenHive:mpp:*:*:*:*:*:*:*:* Versions — — ·—

Remediation

Fix · CNA mpp (ZenHive) Fixed in 0.16.1

Fixed in the same release

Records fixed by the same vendor advisory or release, as the CNA lists them.

Release · 2026-09-06
ZenHive mpp 0.16.1, 0482572b47e1ffe1537ab80ab613d47b92833c2d
2 records Highest priority Priority LOW 2 LOW
Other records, highest priority first
- TI-2026-57068 Unbounded EIP-7702 authorization list in mpp Tempo fee-payer sponsorship inflates gas…Priority LOW 37
Show all 2 records →

Timeline

2026-10-02 Threatist record created from CVE-2026-82751
2026-10-03 Alias added: GHSA-6fjm-7mv9-c325

References

Patch 1

https://github.com/ZenHive/mpp/commit/0482572b47e1ffe1537ab80ab613d47b92833c2d

Advisory 1

https://github.com/ZenHive/mpp/security/advisories/GHSA-rpwj-vrf7-4x36

Other 2

TI-2026-42571 Unbounded max_fee_per_gas in mpp Tempo fee-payer enables single-request wallet drain CVSS 4.0HIGH 8.3
TI-2026-42570 Unbounded access list in mpp Tempo fee-payer inflates gas cost per payment CVSS 4.0HIGH 8.3
TI-2026-42392 Missing gas_limit validation in mpp Tempo fee-payer enables wallet drain CVSS 4.0HIGH 8.2
TI-2026-60473 Session voucher adding no new funds is accepted without a charge in mpp, serving paid resources for free CVSS 4.0HIGH 7.1
TI-2026-47746 On-chain transfer proof is not single-use in mpp EVM payment method, enabling cross-challenge replay CVSS 4.0HIGH 8.7
TI-2026-51635 Resource allocation without limits in ZenHive mpp CVSS 4.0HIGH 8.3

See all 12 →

Sources

This product uses the NVD API but is not endorsed or certified by the NVD. Sources and licences