Medium 6.9Published Sep 22, 2026

CVE-2026-63628mppx: Gas Draining with access list

Updated under an hour ago (2026-10-19 10:00 UTC)

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It affects wevm mppx. Add what you run to find out whether that includes you.

No exploitation reported and no EPSS estimate yet.

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Every CVE for wevm mppx

Exploited in the last 30 days

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.

CVSS: 6.9 MEDIUM (v4.0, CNA)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
Weakness (CWE): CWE-20
Known exploited: Not in CISA's KEV catalog
EPSS (exploitation in the next 30 days): Not loaded for this CVE
Assigned by: GitHub_M
NVD analysis: Awaiting Analysis
Record last updated: Sep 24, 2026
First seen by InfoSec Signals: Oct 9, 2026

Affected products

Affected products

wevm mppx wevm:mppx (from the name)	before 0.8.2	CNA record

References

https://github.com/wevm/mppx/security/advisories/GHSA-vc9j-9wph-qghjx-refsource-confirm
https://github.com/wevm/mppx/pull/602x-refsource-misc
https://github.com/wevm/mppx/commit/24ddcca719ae282977d8747309ed1275ea282b25x-refsource-misc
https://github.com/wevm/mppx/releases/tag/mppx@0.8.2x-refsource-misc

The CVE record on cve.org NVD's entry

The CVE record is authoritative. Products marked “from the name” were identified from the CNA's free-text names, not a CPE, and are matched less certainly. This product uses the NVD API but is not endorsed or certified by the NVD.