mppx: Tempo has a session close voucher bypass vulnerability due to settled amount equality

高 7.5CVE-2026-34209 · GHSA-mv9j-8jvg-j8mr · 31/03/2026 公開 · 24/07/2026 更新

要点

CVE-2026-34209 は mppx (wevm), mppx に影響する深刻度「高」 (CVSS 7.5) の脆弱性です。
今後30日間に悪用される確率（EPSS）：0.37%（全脆弱性の 31.2% より高い）。
対処：0.4.11 以降に更新してください。

パッケージ	影響を受けるバージョン	修正済みバージョン
mppx wevm	`< 0.4.11`	`0.4.11`
mppx npm	`< 0.4.11`	`0.4.11`

概要

Impact

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.

Patches

Fixed in 0.4.11.

Workarounds

There are no workarounds available for this vulnerability.

NVD の説明

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.