---
id: CVE-2026-63183
title: 'OmniAuth: Host Header Injection Vulnerability'
summary: >-
  OmniAuth is a flexible authentication system utilizing Rack middleware. Prior
  to 2.2.0, OmniAuth derives provider callback URLs from request-controlled host
  information when neither a fixed full_host nor framework-level incoming host
  val…
severity: medium
cvss: 6.9
cvssVector: 'CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:L/VI:L/VA:N/SC:N/SI:L/SA:N'
cvssSource: cna
cwe:
  - CWE-346
vendor: omniauth
product: omniauth
affected:
  - omniauth < 2.2.0
ssvc:
  exploitation: none
  automatable: 'no'
  technicalImpact: partial
  timestamp: '2026-11-05T19:19:56.610534Z'
published: '2026-11-04'
updated: '2026-11-05'
sourceUpdated: '2026-11-05T19:20:06.749Z'
source: CVEORG
sourceUrl: 'https://www.cve.org/CVERecord?id=CVE-2026-63183'
references:
  - url: >-
      https://github.com/omniauth/omniauth/security/advisories/GHSA-m27g-v28p-f9fx
    label: >-
      https://github.com/omniauth/omniauth/security/advisories/GHSA-m27g-v28p-f9fx
  - url: >-
      https://github.com/omniauth/omniauth/commit/943b44faea242f063fa9230254fe7d60cfcc9c90
    label: >-
      https://github.com/omniauth/omniauth/commit/943b44faea242f063fa9230254fe7d60cfcc9c90
tags:
  - cve.org
epss: 0.00181
epssPercentile: 0.0774
ingestedAt: '2026-11-05T22:38:31.522Z'
---

## Overview

OmniAuth is a flexible authentication system utilizing Rack middleware. Prior to 2.2.0, OmniAuth derives provider callback URLs from request-controlled host information when neither a fixed full_host nor framework-level incoming host validation is configured. A remote unauthenticated client can supply a forged Host header, creating a host header injection risk in applications whose web framework does not verify incoming host headers. Applications using appropriately configured Rails host authorization or a fixed full_host are not affected by this path. This issue is fixed in version 2.2.0.

## Affected

- `omniauth < 2.2.0`

## Remediation

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