Client IP spoofing in Go chi ClientIPFromXFF middleware
Key facts
- Attack vector
- Network
- Privileges required
- None
- User interaction
- None
- Attack complexity
- High
- Attack requirements
- None
- Impact type
- Security bypass
- Confidentiality · integrity · availability
- Low · Low · None
- Fix status
- Partial Red Hat: 15 without a fix
Attack profile from CVSS 4.0 · CNA. Fix status from CNA, GitHub and Red Hat. Impact type from CWE-345.
Summary
The Go chi web framework before 5.4.0 (Go module github.com/go-chi/chi/v5) has a flaw in its ClientIPFromXFF middleware. It skips X-Forwarded-For entries that fall in a trusted CIDR without checking that the direct TCP peer belongs to that CIDR, which is a use of less trusted source (CWE-348). A client that can reach the Go server directly can append a trusted-looking proxy address and choose the client IP that the middleware returns.
Written with Claude Haiku 5.5 from the sources below · 2026-10-30
Description from the CNA
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.
Why it matters now
SSVC decision points
CISA ADP · SSVC 2.0.3
- Exploitation
- Poc
- Automatable
- No
- Technical impact
- Partial
The decision (Track, Attend, Act) also depends on your mission and well-being impact; see CISA's SSVC guide.
Affected products
| Vendor | Product | Affected versions | Fixed in | Status | Source |
|---|---|---|---|---|---|
| go-chi | chi | before 5.4.0 | 5.4.0 | Patch available | CNA |
| — | github.com/go-chi/chi/v5 (Go) | before 5.4.0 | 5.4.0 | Patch available | GHSA-j6qf-3m9c-vwj3 |
- chi Vendorgo-chi Affected before 5.4.0 Fixed in 5.4.0 Patch available CNA
- github.com/go-chi/chi/v5 (Go) Vendor— Affected before 5.4.0 Fixed in 5.4.0 Patch available GHSA-j6qf-3m9c-vwj3
Remediation
Upgrade chi and github.com/go-chi/chi/v5 to 5.4.0. Red Hat lists these products as affected without a fix: Logging Subsystem for Red Hat OpenShift and Red Hat Quay 3 (no fix planned), Web Terminal and Zero Trust Workload Identity Manager (Tech Preview) (no fix planned), and Multicluster Engine for Kubernetes, OpenShift Pipelines, OpenShift Serverless, Red Hat Advanced Cluster Management for Kubernetes 2, Red Hat Enterprise Linux 8, Red Hat OpenShift Container Platform 4 and 5, OpenShift Dev Spaces, OpenShift distributed tracing 3, Red Hat Satellite 6 and Red Hat Trusted Artifact Signer (no fix listed).
Written with Claude Haiku 5.5 from the sources below · 2026-10-30
- Fix · CNA chi (go-chi) Fixed in 5.4.0
- Fix · GHSA-j6qf-3m9c-vwj3 github.com/go-chi/chi/v5 (Go) Fixed in 5.4.0 Advisory →
Vendor assessments
Red Hat
Red Hat rating: Moderate. Red Hat's page for this CVE →
| Product | Status | Plan or fix |
|---|---|---|
| Logging Subsystem for Red Hat OpenShift | Affected | No fix planned: Out of support scope |
| Multicluster Engine for Kubernetes | Affected | No fix yet: Fix deferred |
| OpenShift Pipelines | Affected | No fix yet: Fix deferred |
| OpenShift Serverless | Affected | No fix yet: Fix deferred |
| Red Hat Advanced Cluster Management for Kubernetes 2 | Affected | No fix yet: Fix deferred |
| Red Hat Enterprise Linux 8 | Affected | No fix yet: Fix deferred |
| Red Hat OpenShift Container Platform 4 | Affected | No fix yet: Fix deferred |
| Red Hat OpenShift Container Platform 5 | Affected | No fix yet: Fix deferred |
| Red Hat OpenShift Dev Spaces | Affected | No fix yet: Fix deferred |
| Red Hat OpenShift distributed tracing 3 | Affected | No fix yet: Fix deferred |
| Red Hat Quay 3 | Affected | No fix planned: Out of support scope |
| Red Hat Satellite 6 | Affected | No fix yet: Fix deferred |
| Red Hat Trusted Artifact Signer | Affected | No fix yet: Fix deferred |
| Red Hat Web Terminal | Affected | No fix planned: Out of support scope |
| Zero Trust Workload Identity Manager - Tech Preview | Affected | No fix planned: Out of support scope |
Timeline
- 2026-10-21 Threatist record created from CVE-2026-114437
- 2026-10-21 Alias added: GHSA-7cgw-qmxx-7fc2
- 2026-10-21 CISA SSVC decision points changed
- 2026-10-23 Affected versions changed · Red Hat
- 2026-10-23 CVSS score added · Red Hat
- 2026-10-23 Alias added: GHSA-j6qf-3m9c-vwj3
- 2026-10-23 Fix available: Go/github.com/go-chi/chi/[email protected] · GHSA-j6qf-3m9c-vwj3
- 2026-10-23 CVSS score added · GHSA-j6qf-3m9c-vwj3
- 2026-10-23 Weakness changed · GHSA-j6qf-3m9c-vwj3
- 2026-10-23 7 new references · GHSA-j6qf-3m9c-vwj3
- 2026-10-30 Affected versions changed · Red Hat
References
Other 6
- https://www.tenable.com/security/research/tra-2026-66
- https://github.com/go-chi/chi/security/advisories/GHSA-j6qf-3m9c-vwj3
- https://github.com/go-chi/chi/pull/1214
- https://github.com/go-chi/chi/commit/7f9b7448f51d28804fac98c0a17bc2a7cec1079f
- https://github.com/go-chi/chi
- https://github.com/go-chi/chi/releases/tag/v5.4.0
More go-chi vulnerabilities
- TI-2026-51042 go-chi chi before 5.3.0 IP Spoofing via RealIP Middleware CVSS 4.0MEDIUM 6.9
- TI-2026-51041 go-chi chi v5.2.1 IP Spoofing via X-Forwarded-For Header CVSS 4.0MEDIUM 6.9
- TI-2026-82170 Authentication bypass in go-chi chi SupressNotFound middleware CVSS 4.0MEDIUM 6.3
- TI-2026-85173 Open redirect in go-chi chi RedirectSlashes middleware CVSS 4.0MEDIUM 5.1
- TI-2025-43521 go-chi chi before v5.2.2 Open Redirect via RedirectSlashes CVSS 4.0MEDIUM 5.1
- TI-2026-51043 go-chi chi 0.9.0 before 5.3.0 IP Spoofing via X-Forwarded-For CVSS 4.0MEDIUM 6.9
Sources
- CVE-2026-114437 · CVE Program
- CVE-2026-114437 · NVD
- FIRST EPSS
- GHSA-7cgw-qmxx-7fc2 · GitHub Advisory Database · CC BY 4.0
- GHSA-j6qf-3m9c-vwj3 · GitHub Advisory Database · CC BY 4.0
- CVE-2026-114437 · Red Hat security data · CC BY 4.0
This product uses the NVD API but is not endorsed or certified by the NVD. Sources and licences