Vulnerability record · CVE-2026-34209 · published 31 March 2026
CVE-2026-34209: Wevm mppx authentication bypass by capture-replay vulnerability
Wevm · Mppx
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.
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.
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:H/A:N
Affected products
1 vulnerable configurations from NVD's CPE data, grouped by vendor and product.
References
| Link | Tags |
|---|---|
| https://github.com/wevm/mppx/commit/94088246ee18f21b5d6be40d9e7a464f5a280bfb | Patch |
| https://github.com/wevm/mppx/releases/tag/[email protected] | Release Notes |
| https://github.com/wevm/mppx/security/advisories/GHSA-mv9j-8jvg-j8mr | PatchVendor Advisory |
Track CVE-2026-34209 inside VULONE
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Related vulnerabilities
Same products first, then exploited flaws of the same weakness class.
Source: NIST National Vulnerability Database (record CVE-2026-34209), CISA KEV, FIRST EPSS (scores of 2026-09-27). This page is refreshed as NVD updates the record.
