---
id: GHSA-xvg2-cgv6-6h7v
title: 'netfoil: Incorrect block responses could lead to localhost traffic'
summary: 'netfoil: Incorrect block responses could lead to localhost traffic'
severity: high
cwe:
  - CWE-693
vendor: tinfoil-factory
product: github.com/tinfoil-factory/netfoil
ecosystem: go
affected:
  - github.com/tinfoil-factory/netfoil < 0.4.0
patched:
  - github.com/tinfoil-factory/netfoil 0.4.0
published: '2026-07-29'
updated: '2026-07-29'
source: GHSA
sourceUrl: 'https://github.com/advisories/GHSA-xvg2-cgv6-6h7v'
references:
  - url: >-
      https://github.com/tinfoil-factory/netfoil/security/advisories/GHSA-xvg2-cgv6-6h7v
  - url: 'https://github.com/tinfoil-factory/netfoil/pull/33'
  - url: >-
      https://github.com/tinfoil-factory/netfoil/commit/891d3513c77999a9deef9f23506807d9653ee448
  - url: 'https://github.com/tinfoil-factory/netfoil/releases/tag/v0.4.0'
  - url: 'https://github.com/advisories/GHSA-xvg2-cgv6-6h7v'
tags:
  - ghsa
  - go
ingestedAt: '2026-07-29T17:48:50.094Z'
---

## Overview

### Summary
`0.0.0.0` was used instead of NXDOMAIN for block responses. On Linux, which is the target platform for netfoil, the `0.0.0.0` is sent to localhost rather than just dropped.

### Impact
Unintended traffic could be sent to localhost. Impact depends on running services and firewall rules.

## Affected packages

- `github.com/tinfoil-factory/netfoil < 0.4.0`

## Remediation

Upgrade to a patched release:

- `github.com/tinfoil-factory/netfoil 0.4.0`