VulnerabilityAwaiting Analysis

CVE-2026-63627

mppx is a TypeScript interface for machine payments protocol.

MEDIUM 6.9EPSS 0.52%

Does this matter?

Lower severity and a low EPSS score (0.52%). Track it; it rarely justifies an emergency change on its own.

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 4.0: 6.9 MEDIUMCVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:L/SC:N/SI:N/SA:N/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/M
EPSS: 0.52% probability · 44th percentile
Public exploits: None in Exploit-DB
CISA KEV: Not listed
Weakness: CWE-20
Source: security-advisories@github.com

EPSS trend

EPSS moved from 0.5% on 23 September 2026 to 0.5% on 26 October 2026.

References

Source: NVD record, EPSS from FIRST.org, KEV from CISA, exploits from Exploit-DB. Refreshed daily. Download this record as JSON.