# CVE-2026-114437: Chi Client IP Spoofing in ClientIPFromXFF via X-Forwarded-For


- **Severity:** Medium 6.3 (`CVSS:4.0/AV:N/AC:H/AT:N/PR:N/UI:N/VC:L/VI:L/VA:N/SC:N/SI:N/SA:N`)
- **Exploited in the wild:** Not known
- **Fix available:** Yes
- **Published:** 21 Oct 2026
- **Updated:** 21 Oct 2026
- **Also known as:** DEBIAN-CVE-2026-114437, ECHO-461c-5390-d147, GHSA-j6qf-3m9c-vwj3, MINI-4fmj-378w-c278, MINI-5mfm-3xjf-f349, MINI-78vx-r3r5-v277, MINI-87cp-rxfp-mq2r, MINI-cr6x-64f6-cfwx, MINI-p7hg-jf77-p3m2, MINI-w98x-4pfr-2w84, UBUNTU-CVE-2026-114437, openSUSE-SU-2026:12290-1

## What is CVE-2026-114437?

CVE-2026-114437 is a medium-severity vulnerability in go-chi chi, published on 21 Oct 2026. 

### Official description

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.

Weakness: CWE-348 (Use of Less Trusted Source)

## Which versions are affected by CVE-2026-114437?

2 open source packages ship an affected version, including github.com/go-chi/chi/v5.


| Package | Ecosystem | Affected | Fixed in |
| --- | --- | --- | --- |
| `github.com/go-chi/chi/v5` | Go | All versions | 5.4.0 |
| `github.com/go-chi/chi/v5` | Go | All versions | 5.4.0 |
| `hauler` | openSUSE:Tumbleweed | All versions | 2.1.2-2.1 |

## How do I fix CVE-2026-114437?

Upgrade github.com/go-chi/chi/v5 to 5.4.0 or later.

## Is CVE-2026-114437 being exploited?

It is not confirmed as exploited in the wild, but public exploit code for CVE-2026-114437 exists.

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2026-114437 and fix it if it is affected.

What it is: CVE-2026-114437 is a medium-severity vulnerability in go-chi chi, published on 21 Oct 2026. 
Exploitation: It is not confirmed as exploited in the wild, but public exploit code for CVE-2026-114437 exists.

Affected packages and fixed versions:
- github.com/go-chi/chi/v5 (Go): affected all versions; fixed in 5.4.0
- github.com/go-chi/chi/v5 (Go): affected all versions; fixed in 5.4.0

Task:
1. Search the dependency manifests and lockfiles (for example package.json, package-lock.json, requirements.txt, poetry.lock, uv.lock, pom.xml, build.gradle, go.mod, Cargo.lock, Gemfile.lock) and any Dockerfiles for the affected packages, including transitive dependencies.
2. If an affected version is in use, upgrade it to the fixed version for its release line with the project's package manager, so the lockfile is regenerated. Prefer the smallest upgrade that fixes it.
3. If there is no fix, or the upgrade would break the build, do not guess: explain the risk and the safest workaround instead.
4. Run the tests and summarise what changed and why.
5. If nothing in the project is affected, say so and change nothing.

Reference: https://insights.sbomify.com/CVE-2026-114437/ (Markdown: https://insights.sbomify.com/CVE-2026-114437/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2026-114437
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-114437
- OSV: https://osv.dev/vulnerability/CVE-2026-114437

---
From sbomify Insights: https://insights.sbomify.com/CVE-2026-114437/
Summaries are generated and may contain mistakes; the official description above is the record.