CVE-2026-63628
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, the fee-payer cosigning path in src/tempo/internal/fee-payer.ts copied a client-supplied access_list from a 0x78 FeePayerEnvelope without validating its length or contents. Because EIP-2930 access-list entries consume intrinsic gas even when the listed addresses are never used, a client could add fabricated address-only entries and cause the server fee_payer wallet to pay unnecessary transaction fees. The demonstrated 180-entry list remained within the 500,000 gas policy cap, 16 KB header limit, and RPC simulation budget while increasing the fee by approximately 9.4 times. 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-vc9j-9wph-qghj security-advisories@github.com
- https://github.com/wevm/mppx/security/advisories/GHSA-vc9j-9wph-qghj 134c704f-9b21-4f2e-91b3-4a467353bcc0