# CVE-2026-114437: Go Chi ClientIPFromXFF IP spoofing via X-Forwarded-For

Source: https://junglewise.ai/threats/cve-2026-114437-in-the-golang-chi-web-framework-the-clientipfromxff-middleware  
Publisher: Junglewise Threat Intelligence, https://junglewise.ai/threats  
Published: 2026-10-21. Updated: 2026-10-21  
License: CC BY 4.0 with a link back

CVE-2026-114437 · Severity: medium · CVSS 4.8 · Published 2026-10-21

The Chi web framework's ClientIPFromXFF middleware in Go, used to extract the real client IP from proxy headers, fails to verify that the direct TCP connection originates from a trusted proxy server. An attacker who can reach the server directly can forge an X-Forwarded-For header with a spoofed IP address to bypass IP-based access controls, converting a denied request into an allowed one.

Technologies: [github.com/go-chi/chi/v5 (Go)](https://junglewise.ai/threats/technologies/github-com-go-chi-chi-v5), [Go-Chi Chi](https://junglewise.ai/threats/technologies/chi). Vendors: [Go](https://junglewise.ai/threats/vendors/go), [Go-Chi](https://junglewise.ai/threats/vendors/go-chi).

## Quick answers

**Is CVE-2026-114437 exploited in the wild?** No. Junglewise Threat Intelligence has no report of CVE-2026-114437 being exploited in the wild.

**How severe is CVE-2026-114437?** Medium severity, with a CVSS score of 4.8, published 21 October 2026.

**Which products and versions are affected?** github.com/go-chi/chi/v5 (Go) <= 5.3.2, SEMVER:introduced=0,fixed=5.4.0; Go-Chi Chi before 5.4.0.

**Is there a fix for CVE-2026-114437?** Yes. github.com/go-chi/chi/v5 (Go): upgrade to 5.4.0 or later. Junglewise finds every place you run it, drafts the upgrade and applies it once you approve.

**How is CVE-2026-114437 attacked?** It is attacked over the network.

**Am I affected by CVE-2026-114437?** Check whether you run github.com/go-chi/chi/v5 (Go) or Go-Chi Chi at an affected version. Junglewise does that check for you around the clock: connect your code, cloud and domains, and it matches new vulnerabilities like this one against what you actually run and tells you when one reaches you.

## How to fix

- github.com/go-chi/chi/v5 (Go): upgrade to 5.4.0 or later

  ```sh
  go get github.com/go-chi/chi/v5@v5.4.0
  ```


## Technical details

The ClientIPFromXFF middleware skips X-Forwarded-For entries in configured trusted CIDRs but does not validate that http.Request.RemoteAddr (the direct peer) belongs to a trusted CIDR before processing the header chain. An unauthenticated remote attacker can append a trusted-proxy IP and a spoofed client IP to X-Forwarded-For, causing middleware.GetClientIP to return an arbitrary address. The vulnerability requires the server to be directly reachable and relies on an application that gates access based on client IP.

## Affected products

- Go Chi Chi before 5.4.0

## Identifiers

- CVE-2026-114437
- GHSA-j6qf-3m9c-vwj3

## Timeline

- 2026-10-12: disclosed
- 2026-10-21: patched

## References

- [https://pkg.go.dev/](https://pkg.go.dev/)
- [https://github.com/go-chi/chi/security/advisories/GHSA-j6qf-3m9c-vwj3](https://github.com/go-chi/chi/security/advisories/GHSA-j6qf-3m9c-vwj3)

## Related threats

- [go-chi chi open redirect in RedirectSlashes middleware](https://junglewise.ai/threats/cve-2026-122132-go-chi-chi-5-2-2-through-5-5-0-contains-an-open-redirect)
- [Chi web framework client IP spoofing via X-Forwarded-For](https://junglewise.ai/threats/duplicate-advisory-chi-client-ip-spoofing-in-clientipfromxff-via-x-f73190e1)
- [GO-2026-5775 - Chi Middleware vulnerable to IP spoofing via X-Forwarded-For header in github.com/go-chi/chi](https://junglewise.ai/threats/cve-2026-72817-chi-middleware-vulnerable-to-potential-ip-spoofing-via-x)
- [GO-2026-5777 - Chi's RealIP Middleware allows IP spoofing via unvalidated X-Forwarded-For header in github.com/go-chi/chi](https://junglewise.ai/threats/cve-2026-72816-chi-s-realip-middleware-allows-ip-spoofing-via-unvalidated-x)
- [GO-2026-5774 - Chi has an IP spoofing vulnerability in middleware.RealIP in github.com/go-chi/chi](https://junglewise.ai/threats/cve-2026-72815-chi-has-an-ip-spoofing-vulnerability-in-middleware-realip)