{"id":"CVE-2026-34209","aliases":["EUVD-2026-17455","GHSA-mv9j-8jvg-j8mr"],"status":"published","title":"mppx: Tempo has a session close voucher bypass vulnerability due to settled amount equality","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 \"\u003c\" instead of \"\u003c=\" 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.","severity":{"version":"3.1","score":7.5,"vector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:H/A:N","level":"high","assessor":"cna","from":"cve"},"epss":{"day":"2026-11-10","score":0.00373,"percentile":0.31508,"model":"v2026.06.15"},"facts":{"in_kev":false,"known_exploited":false,"public_exploit":false,"fix_available":true},"cwes":["CWE-294"],"published":"2026-03-29T15:10:03Z","modified":"2026-10-28T02:30:34Z","fixes":[{"ecosystem":"npm","package":"mppx","fixed_in":["0.4.11"],"sources":["ghsa","osv"]}],"affected":[{"source":"ghsa","ecosystem":"npm","package":"mppx","ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"},{"fixed":"0.4.11"}]}]},{"source":"osv","ecosystem":"npm","package":"mppx","ranges":[{"type":"SEMVER","events":[{"introduced":"0"},{"fixed":"0.4.11"}]}]}],"products":[{"vendor":"wevm","product":"mppx"}],"references":[{"url":"https://github.com/wevm/mppx/security/advisories/GHSA-mv9j-8jvg-j8mr","tags":["x_refsource_CONFIRM","Patch","Vendor Advisory","advisory","web"]},{"url":"https://github.com/wevm/mppx/commit/94088246ee18f21b5d6be40d9e7a464f5a280bfb","tags":["x_refsource_MISC","Patch","fix","web"]},{"url":"https://github.com/wevm/mppx/releases/tag/mppx@0.4.11","tags":["x_refsource_MISC","Release Notes","web"]},{"url":"https://nvd.nist.gov/vuln/detail/CVE-2026-34209","tags":["advisory"]},{"url":"https://github.com/advisories/GHSA-mv9j-8jvg-j8mr"},{"url":"https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/34xxx/CVE-2026-34209.json","tags":["advisory"]},{"url":"https://github.com/wevm/mppx","tags":["package"]}],"sources":{"cve":[{"id":"CVE-2026-34209","title":"mppx: Tempo has a session close voucher bypass vulnerability due to settled amount equality","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 \"\u003c\" instead of \"\u003c=\" 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.","status":"published","published":"2026-03-31T14:10:46.416Z","modified":"2026-04-02T15:13:32.047Z","cvss":[{"version":"3.1","score":7.5,"vector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:H/A:N","level":"high","assessor":"cna"}],"cwes":["CWE-294"],"updated_at":"2026-11-02T14:20:14.302133Z"}],"euvd":[{"id":"EUVD-2026-17455","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 \"\u003c\" instead of \"\u003c=\" 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.","status":"published","published":"2026-03-31T14:10:46Z","modified":"2026-04-02T15:13:32Z","cvss":[{"version":"3.1","score":7.5,"vector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:H/A:N","level":"high"}],"updated_at":"2026-11-02T19:25:22.606516Z"}],"ghsa":[{"id":"GHSA-mv9j-8jvg-j8mr","title":"mppx: Tempo has a session close voucher bypass vulnerability due to settled amount equality","description":"### Impact\n\nThe `tempo/session` cooperative close handler validated the close voucher amount using `\u003c` instead of `\u003c=` 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.\n\n### Patches\n\nFixed in 0.4.11.\n\n### Workarounds\n\nThere are no workarounds available for this vulnerability.","status":"published","published":"2026-03-29T15:10:03Z","modified":"2026-03-31T18:51:06Z","cvss":[{"version":"3.1","score":7.5,"vector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:H/A:N","level":"high"}],"cwes":["CWE-294"],"updated_at":"2026-11-02T14:39:47.075804Z"}],"nvd":[{"id":"CVE-2026-34209","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 \"\u003c\" instead of \"\u003c=\" 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.","status":"published","published":"2026-03-31T15:16:18.03Z","modified":"2026-07-24T21:10:00.143Z","cvss":[{"version":"3.1","score":7.5,"vector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:H/A:N","level":"high","assessor":"secondary"}],"cwes":["CWE-294"],"updated_at":"2026-11-02T14:12:12.261218Z"}],"osv":[{"id":"CVE-2026-34209","title":"mppx: Tempo has a session close voucher bypass vulnerability due to settled amount equality","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 \"\u003c\" instead of \"\u003c=\" 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.","status":"published","published":"2026-03-31T14:10:46.416Z","modified":"2026-10-28T02:30:34.370917824Z","cvss":[{"version":"3.1","score":7.5,"vector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:H/A:N","level":"high"}],"cwes":["CWE-294"],"updated_at":"2026-11-02T15:45:02.247031Z"},{"id":"GHSA-mv9j-8jvg-j8mr","title":"mppx: Tempo has a session close voucher bypass vulnerability due to settled amount equality","description":"### Impact\n\nThe `tempo/session` cooperative close handler validated the close voucher amount using `\u003c` instead of `\u003c=` 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.\n\n### Patches\n\nFixed in 0.4.11.\n\n### Workarounds\n\nThere are no workarounds available for this vulnerability.","status":"published","published":"2026-03-29T15:10:03Z","modified":"2026-03-31T19:05:19.688464Z","cvss":[{"version":"3.1","score":7.5,"vector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:H/A:N","level":"high"}],"cwes":["CWE-294"],"updated_at":"2026-11-02T15:46:52.170928Z"}]}}