Description
Vyper 0.4.0b1 through 0.5.0b1 miscompiles unfoldable constants and omitted default arguments from imported modules, because parse_Name resolves their names in the using function's scope rather than at declaration. When a contract's parameter, local, or loop variable shares such a name, attacker-influenced input can replace the intended value, including out-of-range values for narrow types such as uint8, corrupting validation or accounting logic.
References2
Metrics
- CVSS 3.1
-
8.4
HIGH
Score source: CNA
CVSS:3.1/AV:L/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H - CVSS 4.0
-
8.6
HIGH
Score source: CNA
CVSS:4.0/AV:L/AC:L/AT:N/PR:N/UI:N/VC:H/VI:H/VA:H/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/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X - EPSS — exploit probability
- 0% percentile: 7 · as of 8 November 2026
- CWE
- CWE-706
Could this be exploited in your environment?
A patch closes the known hole. A penetration test shows what an attacker can still reach — with proof.