---
title: "GHSA-8x4m-qw58-3pcx: mppx has multiple payment bypass and griefing vulnerabilities"
url: https://erroneo.us/security/ghsa/GHSA-8x4m-qw58-3pcx/
description: "GHSA-8x4m-qw58-3pcx (critical, npm): mppx has multiple payment bypass and griefing vulnerabilities. Impact Multiple vulnerabilities were discovered in…"
type: advisory
section: "Security Digest"
date_published: 2026-03-29
date_modified: 2026-03-29
publisher: erroneo.us
author: erroneo.us Security Desk
ghsa: "GHSA-8x4m-qw58-3pcx"
license: All rights reserved. Quote with attribution and a link.
---

# GHSA-8x4m-qw58-3pcx: mppx has multiple payment bypass and griefing vulnerabilities

## Affected packages

- npm `mppx` < 0.4.8 → fixed: 0.4.8

## Details

Impact Multiple vulnerabilities were discovered in tempo/charge and tempo/session which allowed for undesirable behaviors, including: - Replaying tempo/charge transaction hashes across push/pull modes, across charge/session endpoints, and via concurrent requests - Performing free tempo/charge requests due to missing transfer log verification in pull-mode - Replaying tempo/charge credentials across routes via cross-route scope confusion (memo/splits not included in scope binding) - Manipulating the fee payer of a tempo/charge handler into paying for requests (missing sender signature before co-signing) - Bypassing tempo/session voucher signature verification - Piggybacking off existing tempo/session channels via settle voucher reuse and weak channel ID binding - Performing free tempo/session requests by exploiting channel reopen without on-chain settled state - Accepting deductions on finalized tempo/session channels - Bypassing payment on free routes via method-mismatch fallback - Griefing tempo/session channels via force-close detection bypass (closeRequestedAt not persisted) Patches Fixed in 0.4.8. Workarounds There are no workarounds available for these vulnerabilities.

## Sources

- [GitHub Advisory GHSA-8x4m-qw58-3pcx](https://github.com/advisories/GHSA-8x4m-qw58-3pcx)
- [github.com](https://github.com/wevm/mppx/security/advisories/GHSA-8x4m-qw58-3pcx)

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Source page: https://erroneo.us/security/ghsa/GHSA-8x4m-qw58-3pcx/ · Security Digest: https://erroneo.us/security/ · More: https://erroneo.us/llms.txt