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

> Attackers can replay payment credentials to consume unlimited resources without paying, affecting users of the mppx TypeScript library.

- **Severity:** Medium 6.0 (`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`)
- **Exploited in the wild:** Not known
- **Login needed:** Any signed-in user
- **Attackable:** Over the internet
- **Victim action needed:** Not needed
- **Fix available:** Yes
- **Published:** 31 Mar 2026
- **Updated:** 31 Mar 2026
- **Also known as:** GHSA-8mhj-rffc-rcvw

## What is CVE-2026-34210?

CVE-2026-34210 is a medium-severity vulnerability in wevm mppx, published on 31 Mar 2026. Any signed-in user can exploit it over the network, with no action from the victim.

### Official 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.

Weakness: CWE-697 (Incorrect Comparison)

## Which versions are affected by CVE-2026-34210?

2 open source packages ship an affected version, including mppx. It affects 1 product.


| Package | Ecosystem | Affected | Fixed in |
| --- | --- | --- | --- |
| `mppx` | npm | All versions | 0.4.11 |
| `mppx` | npm | All versions | 0.4.11 |

Products: Wevm Mppx.

## How do I fix CVE-2026-34210?

Upgrade mppx to 0.4.11 or later.

## Is CVE-2026-34210 being exploited?

There is no known exploitation of CVE-2026-34210 in the wild and no public exploit code.

## Other vulnerabilities in wevm mppx

- [CVE-2026-34209](https://insights.sbomify.com/CVE-2026-34209/): mppx: Tempo has a session close voucher bypass vulnerability due to settled amount equality (high 7.5)

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2026-34210 and fix it if it is affected.

What it is: CVE-2026-34210 is a medium-severity vulnerability in wevm mppx, published on 31 Mar 2026. Any signed-in user can exploit it over the network, with no action from the victim.
Exploitation: There is no known exploitation of CVE-2026-34210 in the wild and no public exploit code.

Affected packages and fixed versions:
- mppx (npm): affected all versions; fixed in 0.4.11
- mppx (npm): affected all versions; fixed in 0.4.11

Task:
1. Search the dependency manifests and lockfiles (for example package.json, package-lock.json, requirements.txt, poetry.lock, uv.lock, pom.xml, build.gradle, go.mod, Cargo.lock, Gemfile.lock) and any Dockerfiles for the affected packages, including transitive dependencies.
2. If an affected version is in use, upgrade it to the fixed version for its release line with the project's package manager, so the lockfile is regenerated. Prefer the smallest upgrade that fixes it.
3. If there is no fix, or the upgrade would break the build, do not guess: explain the risk and the safest workaround instead.
4. Run the tests and summarise what changed and why.
5. If nothing in the project is affected, say so and change nothing.

Reference: https://insights.sbomify.com/CVE-2026-34210/ (Markdown: https://insights.sbomify.com/CVE-2026-34210/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2026-34210
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-34210
- OSV: https://osv.dev/vulnerability/CVE-2026-34210

---
From sbomify Insights: https://insights.sbomify.com/CVE-2026-34210/
Summaries are generated and may contain mistakes; the official description above is the record.