What is CVE-2026-34209?

CVE-2026-34209 is a high-severity vulnerability in Wevm Mppx, classified under Authentication Bypass by Capture-replay. CVSS score: 7.5/10. Published 2026-03-31.

How severe is CVE-2026-34209?

High severity. CVSS v3 base score is 7.5 out of 10.

Vulnerability in Wevm Mppx

CVE-2026-34209

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 attacke…

EPSS: 0.000 (2.1th percentile) — read the EPSS interpretation.

CVSS v3 metric

CVSS v3 base score 7.5 (High). Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:H/A:N.

Affected products

Wevm Mppx — versions < 0.4.11

Weakness classification (CWE)

CWE-294 — Authentication Bypass by Capture-replay

References

https://github.com/wevm/mppx/security/advisories/GHSA-mv9j-8jvg-j8mr (x_refsource_CONFIRM)
https://github.com/wevm/mppx/commit/94088246ee18f21b5d6be40d9e7a464f5a280bfb (x_refsource_MISC)
https://github.com/wevm/mppx/releases/tag/mppx@0.4.11 (x_refsource_MISC)

Frequently asked questions

What is CVE-2026-34209?: CVE-2026-34209 is a high-severity vulnerability in Wevm Mppx, classified under Authentication Bypass by Capture-replay. CVSS score: 7.5/10. Published 2026-03-31.
How severe is CVE-2026-34209?: High severity. CVSS v3 base score is 7.5 out of 10.