Zenhive Machine Payments Protocol
CVE-2026-67581
Authentication Bypass by Capture-replay in ZenHive mpp allows an unauthenticated remote client to obtain paid resources by resubmitting one settled on-chain transfer. MPP.Methods.EVM.verify/2 accepts a transaction-hash credential and matches a transfer purely on token, to and amount (ERC-20) or to and value (native). It binds the proof neither to the challenge being verified nor to any record of prior use, and the generic MPP.Plug dedup store keys on challenge.id, which is regenerated for every 402 response. On a static-price route, a single historical transfer matching the charge therefore satisfies an unbounded number of later charges, including transfers an attacker can read off a public block explorer. This issue affects mpp: from 0.3.0 before 0.6.3.
What this means for your business
- It affects Zenhive Machine Payments Protocol. It matters if your company, or a supplier that handles your data, runs it.
- An attacker can use it remotely, over a network, without a login, and without anyone at your company clicking anything.
- FIRST's prediction model gives it a 0.4% chance of attack attempts being seen in the next 30 days, ranking above 34% of all known flaws.
What to do
- 1Check whether your company or your suppliers run Zenhive Machine Payments Protocol, and which version. The affected versions are listed further down this page.
- 2If you do, apply the vendor's fix. A patch or vendor advisory has been published.
Fastnexa security experts
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Scoring
- CVSS
- 7.5 (v3.1)
- Vector
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:H/A:N- CVSS v4
- 8.7
- Weakness
- CWE-294
- Assigned by
- 6b3ad84c-e1a6-4bf7-a703-f496b71e49db
Dates
- Published
- 2026-08-19
- Last modified
- 2026-09-10
- Sources
- NVD
Affected products
- Zenhive Machine Payments Protocol0.3.0 - 0.6.4
As listed in the NVD configuration data. Not a statement about your estate.