Vulnerability · Published Oct 22, 2026 · Assigned by VulnCheck

CVE-2026-114663Vyper 0.4.0b1 through 0.5.0b1 Name Shadowing of Imported Constants and Default Arguments

High 8.4

In plain English

A high-severity security flaw in vyper from vyperlang. There are no confirmed reports of exploitation so far. The chance it is exploited in the next 30 days is estimated at 0.2% (higher than 7% of all known vulnerabilities).

Severity (CVSS 3.1)8.4High

Exploit odds (30 days)0.2%top 92.8% of all CVEs

Exploited in the wildNo reportsCISA SSVC: none

Attack toolingNoneno public tooling known

Official 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.

Affected products (as reported)

Vendor	Product	Versions
vyperlang	vyper	0.4.0b1 – through 0.5.0b1

Weakness: CWE-706 · Vector: CVSS:3.1/AV:L/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H

References

GitHub Security Advisory (GHSA-2489-32vh-8rrc) vendor-advisory
VulnCheck Advisory: Vyper 0.4.0b1 through 0.5.0b1 Name Shadowing of Imported Constants and Default Arguments third-party-advisory