---
id: CVE-2026-114437
title: Chi Client IP Spoofing in ClientIPFromXFF via X-Forwarded-For
summary: >-
  In the Golang Chi web framework, the ClientIPFromXFF middleware skips any
  X-Forwarded-For entry in a configured trusted CIDR but never verifies that the
  direct TCP peer in http.Request.RemoteAddr belongs to that CIDR. A client that
  can r…
severity: medium
cvss: 4.8
cvssVector: 'CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:L/I:L/A:N'
cvssSource: cna
cwe:
  - CWE-348
vendor: go-chi
product: github.com/go-chi/chi/v5
affected:
  - github.com/go-chi/chi/v5 < 5.4.0
ssvc:
  exploitation: poc
  automatable: 'no'
  technicalImpact: partial
  timestamp: '2026-10-21T15:16:38.882767Z'
exploitAvailable: true
published: '2026-10-21'
updated: '2026-10-21'
sourceUpdated: '2026-10-21T17:19:13.809Z'
source: CVEORG
sourceUrl: 'https://www.cve.org/CVERecord?id=CVE-2026-114437'
references:
  - url: 'https://www.tenable.com/security/research/tra-2026-66'
  - url: 'https://github.com/go-chi/chi/security/advisories/GHSA-j6qf-3m9c-vwj3'
tags:
  - cve.org
  - exploit-available
ingestedAt: '2026-10-21T13:57:01.098Z'
---

## Overview

In the Golang Chi web framework, the ClientIPFromXFF middleware skips any X-Forwarded-For entry in a configured trusted CIDR but never verifies that the direct TCP peer in http.Request.RemoteAddr belongs to that CIDR. A client that can reach the Go server directly can therefore append a trusted-looking proxy address and choose the client IP returned by middleware.GetClientIP.

This issue affects chi before 5.4.0.

## Affected

- `github.com/go-chi/chi/v5 < 5.4.0`

## Remediation

Refer to the linked advisories for vendor-supplied fixes and affected version ranges.