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.
History

Tue, 31 Mar 2026 14:30:00 +0000

Type Values Removed Values Added
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.
Title mppx: Tempo has a session close voucher bypass vulnerability due to settled amount equality
Weaknesses CWE-294
References
Metrics cvssV3_1

{'score': 7.5, 'vector': 'CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:H/A:N'}


cve-icon MITRE

Status: PUBLISHED

Assigner: GitHub_M

Published:

Updated: 2026-03-31T14:10:46.416Z

Reserved: 2026-03-26T15:57:52.324Z

Link: CVE-2026-34209

cve-icon Vulnrichment

No data.

cve-icon NVD

Status : Received

Published: 2026-03-31T15:16:18.030

Modified: 2026-03-31T15:16:18.030

Link: CVE-2026-34209

cve-icon Redhat

No data.

cve-icon OpenCVE Enrichment

No data.