CVE-2026-63627

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.

• CWE-20

• 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

Published

Sep 22, 2026

Last Modified

Sep 23, 2026

Status

Awaiting Analysis

• How Strix found a critical auth bypass in etcdStrix autonomously discovered a critical authentication bypass in etcd, later designated CVE-2026-33413.
• Autonomous PentestingAI agents that find and validate exploitable vulnerabilities like this one across your applications.
• PR ReviewsPentest every pull request so vulnerable code is caught before it ships to production.
• AI Penetration TestingHow AI-driven penetration testing continuously covers your attack surface.

• CVE-2026-6360Use after free in FileSystem in Google Chrome prior to 147.0…8.8
• CVE-2026-6361Heap buffer overflow in PDFium in Google Chrome on Windows p…8.3
• CVE-2026-6362Use after free in Codecs in Google Chrome prior to 147.0.772…4.3
• CVE-2026-63621Improper Input Validation, Improper Neutralization of Specia…5.3
• CVE-2026-63622A flaw was found in libvirt. A local attacker, specifically …7.8
• CVE-2026-63623A flaw was found in libvirt. During storage volume clone or …5.5
• CVE-2026-63628mppx is a TypeScript interface for machine payments protocol…6.9
• CVE-2026-6363Type Confusion in V8 in Google Chrome prior to 147.0.7727.10…8.8
• CVE-2026-63630BentoPDF is a client-side PDF toolkit that is self hostable.…3.4
• CVE-2026-63632Open Neural Network Exchange (ONNX) is an open standard for …3.3
• CVE-2026-63633FreeRDP is a free implementation of the Remote Desktop Proto…9.8
• CVE-2026-63635OpenImageIO is a toolset for reading, writing, and manipulat…5.5