How severe is CVE-2026-34210?

No CVSS score has been assigned to CVE-2026-34210 yet. Review the advisory details and affected package list to assess your exposure.

Which packages are affected by CVE-2026-34210?

CVE-2026-34210 affects the following packages: mppx (npm). Ecosystems affected: npm.

How do I fix CVE-2026-34210?

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.

How do I detect CVE-2026-34210 in my npm dependencies?

Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for mppx. O3's reachability analysis confirms whether the vulnerable code path is actually invoked in your application, so you act on real exposure instead of every transitive match.

How do I mitigate CVE-2026-34210 if there is no patch (or I can't update yet)?

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 does O3 Security protect against CVE-2026-34210?

O3 pinpoints whether CVE-2026-34210 is reachable in your code and exactly where to fix it, then blocks exploitation in production at runtime until the patched version is deployed.

Is CVE-2026-34210 actively exploited in the wild?

No public exploit code has been indexed for CVE-2026-34210 yet. This does not mean the vulnerability cannot be exploited — absence of public exploits does not imply safety. Apply the recommended fix and use O3 Security to monitor your exposure.

What is the EPSS score for CVE-2026-34210?

CVE-2026-34210 has an EPSS (Exploit Prediction Scoring System) score of 0.5%, placing it in the 38th percentile of all CVEs. EPSS is maintained by FIRST.org and estimates the probability that a vulnerability will be exploited in the wild within the next 30 days. This score indicates relatively lower exploitation probability, though the CVSS severity should still guide your patching priority.

When was CVE-2026-34210 published, and has it been updated?

CVE-2026-34210 was published on March 31, 2026 and was last updated on April 2, 2026. Advisory data evolves as severity scores, affected ranges, and exploit intelligence are revised — always check the latest version of the advisory before acting.

CVE-2026-34210: mppx

EPSS Exploitation Probability

via FIRST.org ↗

0.5%probability of exploitation in next 30 days

Lower Risk38th percentile+0.48%

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.

Blast Radius

1 pkg affected

Weekly download volume for affected packages — a proxy for how broadly this vulnerability is deployed.

mppxnpm

55Kdownloads / week

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.

Affected Packages

1 total 1 fixed

Ecosystem	Package	Vulnerable range	Fix
📦npm	`mppx`	all versions	0.4.11

Detection & mitigation playbook

Open-source dependency

Detect
Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for mppx. O3's reachability analysis confirms whether the vulnerable code path is actually invoked in your application, so you act on real exposure instead of every transitive match.
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 pinpoints whether CVE-2026-34210 is reachable in your code and exactly where to fix it, then blocks exploitation in production at runtime until the patched version is deployed.

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

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.

O3 Security · Impact-Aware SCA

Is CVE-2026-34210 in your dependencies?

O3 detects CVE-2026-34210 across npm dependencies and uses function-level reachability to confirm whether the vulnerable code path is actually reachable — not just present. No false positives.

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CVE-2026-34210