CVE-2026-34210 — mppx
Fix: wevm/mppx@b2b1a0bCVE-2026-34210 is a CWE-697 vulnerability in mppx. A fix is available for mppx — see the affected versions and patch details below.
mppx has Stripe charge credential replay via missing idempotency check
Exploitation Status
No confirmed exploitation observed yet
- CISA’s own triage has not observed active exploitation or public proof-of-concept code for this CVE as of its last assessment.
Exploitation and automatability from CISA’s SSVC triage for CVE-2026-34210.
EPSS Exploitation Probability
EPSS (Exploit Prediction Scoring System) is a daily probability model maintained by FIRST.org. It estimates the likelihood a CVE will be exploited in production environments within the next 30 days, derived from real-world threat intelligence signals.
Real-World Exposure
How broadly this vulnerability is actually deployed: weekly install volume shows current usage, and reverse-dependency count shows how many other packages break if it stays unpatched.
mppxnpmDescription
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.
Affected Packages
| Ecosystem | Package | Vulnerable range | Fix |
|---|---|---|---|
| 📦npm | mppx | all versions | 0.4.11npm install mppx@0.4.11 |
Detection & mitigation playbook
Open-source dependencyDetect
Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for mppx, including transitive dependencies — a direct dependency you never call can still pull in a vulnerable version.
Fix
Update mppx to 0.4.11 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms CVE-2026-34210 is resolved across your whole dependency graph.
Workarounds
If you can't upgrade right away: gate or disable the affected feature, validate untrusted input at the boundary, and avoid passing attacker-controlled data into the vulnerable path. O3's runtime protection blocks exploitation in production as an interim safeguard until the upgrade lands.
How O3 protects you
O3 Security's impact-aware SCA analyses which vulnerable code paths your application actually calls, so a match like CVE-2026-34210 can be triaged on real exposure rather than presence alone.
Tailored to CVE-2026-34210. Runtime protection reduces exposure until a permanent patch is applied and verified — it complements patching, it doesn't replace it.
Frequently Asked Questions
Is CVE-2026-34210 in your dependencies?
O3 Security finds CVE-2026-34210 across npm dependencies, including transitive ones, and its impact-aware SCA ranks findings by whether your code actually calls the vulnerable path.