# CVE-2026-63183: OmniAuth: Host Header Injection Vulnerability

Status: published. Published: 2026-11-04. Updated: 2026-11-04.

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.

## Remediation

No remediation reported in collected sources

## Affected products and versions

- omniauth / omniauth: < 2.2.0 (affected). Source: CNA: GitHub_M

## Severity and prioritization

- CVSS 4.0: 6.9 (medium); 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; source: CNA: GitHub_M

- CISA KEV: No listing in collected sources

- EPSS: Not available

- SSVC: Not available

- Weaknesses: CWE-346

## Exploit evidence

No exploit evidence in collected sources. This is not proof of no exploitation.

## References

- https://github.com/omniauth/omniauth/security/advisories/GHSA-m27g-v28p-f9fx (CNA: GitHub_M; x_refsource_CONFIRM)

- https://github.com/omniauth/omniauth/commit/943b44faea242f063fa9230254fe7d60cfcc9c90 (CNA: GitHub_M; x_refsource_MISC)

## Provenance

- CNA: GitHub_M: https://www.cve.org/CVERecord?id=CVE-2026-63183; retrieved 2026-11-04; source updated 2026-11-04

Revision: 9e6918e7e4075db358c54eec82fe9067b5c799d0aaa135726f7107361ebed21f

Canonical: https://y2.dev/cve/CVE-2026-63183

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