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, including transitive dependencies — a direct dependency you never call can still pull in a vulnerable version.

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.

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 44th 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.

What type of vulnerability is CVE-2026-34210?

CVE-2026-34210 is classified as CWE-697 (CWE-697). This weakness type describe the underlying flaw category, which helps determine the potential impact and the right class of mitigation.

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 October 28, 2026. Advisory data evolves as severity scores, affected ranges, and exploit intelligence are revised — always check the latest version of the advisory before acting.

📦 npm

Not in CISA KEV

CVE-2026-34210 — mppx

Fix: wevm/mppx@b2b1a0b

CVE-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

Also known asGHSA-8mhj-rffc-rcvw

Published

Mar 31, 2026

Updated

Oct 28, 2026

Affected

1 pkg

Patched

1 / 1

Exploits

None indexed

Exploitation data as of Nov 4, 2026 · OSV.dev, NVD, FIRST.org (EPSS)

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

via FIRST.org ↗

0.5%probability of exploitation in next 30 days

Lower Risk0.00%

Lower risk than most CVEs44th percentile — riskier than 44% of all scored CVEsHighest risk

Probability of exploitation in the next 30 days, from FIRST.org EPSS.

Real-World Exposure

1 pkg affected

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.

141other npm packages depend on this — each one inherits the vulnerability until it's patched upstream

mppxnpm

398Kdownloads / week

Description

Impact

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.

Patches

Fixed in 0.4.11. The server now checks the Idempotent-Replayed header and rejects replayed PaymentIntents.

Workarounds

There are no workarounds available for this vulnerability.

Affected Packages

1 total 1 fixed

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

Affected Products

1 product · 1 configurations

Application

mppxwevm

< 0.4.11

range

Detection & mitigation playbook

Open-source dependency

Detect
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.

Frequently Asked Questions

### Impact 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. ### Patches Fixed in 0.4.11. The server now checks the `Idempotent-Replayed` header and rejects replayed PaymentIntents. ###

O3 Security · Impact-Aware SCA

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