CVE-2026-67581
HighCVSS 8.7Summary
A vulnerability in ZenHive mpp allows an unauthenticated remote client to obtain paid resources by resubmitting one settled on-chain transfer. The EVM verification mechanism does not bind the proof to the challenge or prior use, and deduplication keys are regenerated on every 402 response. On a static-price route, a single historical transfer satisfies an unbounded number of later charges.
Risk Assessment
The organization may suffer financial losses as an attacker can obtain paid resources without cost by exploiting publicly visible transfer data.
Recommendation
Update the mpp component to version 0.6.3 or later, which includes the fix.
Original NVD description (English source)
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.