CVE-2026-63627
Severity not reportedmppx is a TypeScript interface for machine payments protocol.
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.
Affected products
Not reported by the source (unknown — not "none").
Weakness classification (CWE)
Source: NVD / CISA. “NVD-CWE-Other” and “NVD-CWE-noinfo” mean NVD could not assign a specific weakness.
Mitigation & advisories
No vendor advisory or patch reference tagged by NVD. Check the references below.
References
- https://github.com/wevm/mppx/commit/24ddcca719ae282977d8747309ed1275ea282b25 security-advisories@github.com
- https://github.com/wevm/mppx/pull/602 security-advisories@github.com
- https://github.com/wevm/mppx/releases/tag/mppx@0.8.2 security-advisories@github.com
- https://github.com/wevm/mppx/security/advisories/GHSA-727h-3vm5-qwq6 security-advisories@github.com