Replay Attack Affecting mppx package, versions <0.4.11
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Test your applications- Snyk IDSNYK-JS-MPPX-15857147
- published31 Mar 2026
- disclosed29 Mar 2026
- creditsamczsun, Veria Labs
Introduced: 29 Mar 2026
NewCVE-2026-34209 (opens in a new tab)Common Vulnerabilities and Exposures (CVE) are common identifiers for publicly known security vulnerabilities
Common Weakness Enumeration (CWE) is a category system for software weaknesses
How to fix?
Upgrade mppx to version 0.4.11 or higher.
Overview
mppx is a 
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Affected versions of this package are vulnerable to Replay Attack in the tempo/session cooperative close handler due to improper validation of the close voucher amount. An attacker can bypass intended restrictions by submitting a close voucher with an amount exactly equal to the on-chain settled amount, allowing them to close or disrupt the channel without committing new funds.