CVE-2026-34209

Name: CVE-2026-34209
Creator: NVD / NIST
Published: 2026-03-31T15:16:18.03+00:00
License: https://creativecommons.org/publicdomain/zero/1.0/

HIGHCVSS 7.5/10EPSS 0.36%

Last modified Jun 17, 2026

CVE-2026-34209 is a high-severity vulnerability rated 7.5/10 on the CVSS scale. mppx is a TypeScript interface for machine payments protocol. Prior to version 0.4.11, the tempo/session cooperative close handler validated the close voucher amount using "<" instead of "<=" against the on-chain settled amount. EPSS estimates a 0.36% chance of exploitation in the next 30 days.

Description

mppx is a TypeScript interface for machine payments protocol. Prior to version 0.4.11, the tempo/session cooperative close handler validated the close voucher amount using "<" instead of "<=" against the on-chain settled amount. An attacker could submit a close voucher exactly equal to the settled amount, which would be accepted without committing any new funds, effectively closing or griefing the channel for free. This issue has been patched in version 0.4.11.

Metrics

CVSS 3.1

7.5/10

CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:H/A:N

EPSS Probability

0.36%

27.8th percentile

Probability of exploitation in the next 30 days. Learn more

Weakness Enumeration

CWE-294

Affected Software

Vendor	Product	Versions
Wevm	Mppx	< 0.4.11

References

https://github.com/wevm/mppx/commit/94088246ee18f21b5d6be40d9e7a464f5a280bfbPatch
https://github.com/wevm/mppx/releases/tag/mppx@0.4.11Release Notes
https://github.com/wevm/mppx/security/advisories/GHSA-mv9j-8jvg-j8mrPatch, Vendor Advisory

Timeline

Published: Mar 31, 2026
Last Modified: Jun 17, 2026
Status: Analyzed

Frequently Asked Questions

What is CVE-2026-34209?

How severe is CVE-2026-34209?

CVE-2026-34209 has a CVSS score of 7.5/10 (HIGH severity). The EPSS model estimates a 0.36% probability of exploitation in the next 30 days.

How do I fix CVE-2026-34209?

Check the vendor references and advisories linked above for patched versions and mitigation guidance. You can also run a Strix scan to test if your systems are affected.

Are you affected by CVE-2026-34209?

Run a free Strix scan to check your systems for this vulnerability.

Scan your code now

Source: NVD / NIST