---
id: CVE-2026-118681
title: go-chi chi before 5.5.0 Authentication Bypass via SupressNotFound Middleware
summary: >-
  go-chi chi before 5.5.0 contains an authentication bypass in
  middleware.SupressNotFound, which calls Match with the live routing context
  and leaves a mounted router's parameter and child suffix in place for dispatch
  against the outer rou…
severity: low
cvss: 3.7
cvssVector: 'CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:L/I:N/A:N'
cvssSource: cna
cwe:
  - CWE-288
vendor: go-chi
product: chi
affected:
  - chi < 5.5.0
published: '2026-10-28'
updated: '2026-10-28'
sourceUpdated: '2026-10-28T18:59:52.523Z'
source: CVEORG
sourceUrl: 'https://www.cve.org/CVERecord?id=CVE-2026-118681'
references:
  - url: 'https://github.com/go-chi/chi/security/advisories/GHSA-rqrp-8cg2-5958'
    label: GitHub Security Advisory (GHSA-rqrp-8cg2-5958)
  - url: >-
      https://www.vulncheck.com/advisories/go-chi-chi-before-5.5.0-authentication-bypass-via-supressnotfound-middleware
    label: >-
      VulnCheck Advisory: go-chi chi before 5.5.0 Authentication Bypass via
      SupressNotFound Middleware
tags:
  - cve.org
epss: 0.00244
epssPercentile: 0.15591
ingestedAt: '2026-10-29T15:37:07.547Z'
---

## Overview

go-chi chi before 5.5.0 contains an authentication bypass in middleware.SupressNotFound, which calls Match with the live routing context and leaves a mounted router's parameter and child suffix in place for dispatch against the outer router. Unauthenticated attackers can request a mounted path whose suffix matches an outer public route, skipping the mounted authentication middleware and retrieving tenant-scoped data when that outer handler trusts the retained mount parameter.

## Affected

- `chi < 5.5.0`

## Remediation

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