{"cve":"CVE-2026-63627","nvd":{"published":"2026-09-22T20:17:04.763","modified":"2026-09-23T18:12:04.247","status":"Awaiting Analysis","description":"mppx is a TypeScript interface for machine payments protocol. Prior to 0.8.2, FeePayerPolicy in src/tempo/internal/fee-payer.ts used decodeFunctionData to validate fee-sponsored calldata but did not reject trailing bytes. A client could append nonzero padding that increased intrinsic calldata gas while gas_limit and max_fee_per_gas remained within policy caps, causing the server fee_payer wallet to pay substantially more than the decoded transaction required. The tested 16 KB header limit bounded the demonstrated padding to about 5,500 bytes and produced approximately five times the normal transaction fee. This issue is fixed in version 0.8.2.","cvss_v4":{"vector":"CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:L/SC:N/SI:N/SA:N","score":6.9},"cvss_v3":null,"cwes":["CWE-20"],"references":["https://github.com/wevm/mppx/commit/24ddcca719ae282977d8747309ed1275ea282b25","https://github.com/wevm/mppx/pull/602","https://github.com/wevm/mppx/releases/tag/mppx@0.8.2","https://github.com/wevm/mppx/security/advisories/GHSA-727h-3vm5-qwq6"],"products":[],"source":"nvd","synced_at":"2026-10-19T22:56:02.509636177+00:00"},"epss":{"cve":"CVE-2026-63627","score":0.00524,"percentile":0.44446,"date":"2026-10-31"},"kev":null,"osv":[{"id":"GHSA-727h-3vm5-qwq6","url":"https://osv.dev/vulnerability/GHSA-727h-3vm5-qwq6","summary":"mppx: Gas Draining with padding","modified":"2026-09-22T21:00:04.733697025Z","packages":[{"ecosystem":"npm","name":"mppx","purl":"pkg:npm/mppx","ranges":["<0.8.2"],"fixed":["0.8.2"]}]}],"attribution":["This product uses the NVD API but is not endorsed or certified by the NVD.","EPSS scores: FIRST Exploit Prediction Scoring System, https://www.first.org/epss","Known exploited vulnerabilities: CISA Known Exploited Vulnerabilities Catalog, https://www.cisa.gov/known-exploited-vulnerabilities-catalog","Package advisories: OSV (https://osv.dev), from the GitHub Advisory Database, PyPA, Go, RustSec and other ecosystem databases, under CC-BY 4.0 or CC0","CVE records: the CVE Program's CVE List (https://www.cve.org), under its terms of use (https://www.cve.org/Legal/TermsOfUse). CVE is a registered trademark of The MITRE Corporation; this product is not affiliated with the CVE Program."]}