Weakness Type (CWE)

CWE-1284 — CWE-1284 Improper Validation of Specified Quantity in Input

CAPEC

CVSS 4.0 Score

8.2

HIGH

CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N

Vulnerability description

Improper Validation of Specified Quantity in Input in ZenHive mpp allows an unauthenticated remote client to drain the fee-payer wallet, resulting in denial of service for legitimate clients.

When the mpp Elixir library is configured as fee payer (fee_payer: true), the MPP.Methods.Tempo payment method co-signs and broadcasts a client-supplied EVM transaction without first validating that the client-supplied gas_limit is sufficient to complete the intended call. A malicious client can submit a signed transferWithMemo transaction with gas_limit deliberately set just below the amount required for successful execution. The server co-signs the transaction and broadcasts it via rpc_broadcast_sync. The transaction runs out of gas during EVM execution and reverts, but the fee-payer wallet is still charged for the burned gas while the client pays nothing and receives no resource. Repeated requests from one or more malicious clients drain the fee-payer wallet at near-zero cost to the attacker, ultimately preventing the server from sponsoring gas for legitimate payment requests.

The wait_for_confirmation = false (optimistic) path is also affected: it invokes simulate_payment_call via eth_call, but that simulation omits the gas parameter and therefore does not catch out-of-gas conditions.

This issue affects mpp: from 0.2.0 before 0.6.0.

Affected

pkg:hex/mpp

Module Source File Routine
MPP.Methods.Tempo lib/mpp/methods/tempo.ex MPP.Methods.Tempo.broadcast_and_verify/7
Status Type Version Changes / Fixed in
affected semver ⓘ 0.2.0 < 0.6.0

pkg:github/ZenHive/mpp

Module Source File Routine
MPP.Methods.Tempo lib/mpp/methods/tempo.ex MPP.Methods.Tempo.broadcast_and_verify/7
Status Type Version Changes / Fixed in
affected git ⓘ d29d54e507 < d84e3e528d

Configurations

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.

References

Credits

  • Finder: Kian Kai Ang
  • Remediation developer: E.FU
  • Analyst: Jonatan Männchen / EEF

CVE record as JSON:  GET /cves/CVE-2026-59252.json
OSV record as JSON:  GET /osv/EEF-CVE-2026-59252.json