# CVE-2026-39394: CI4MS has an .env CRLF Injection via Unvalidated `host` Parameter in Install Controller

> Attackers can inject arbitrary configuration directives into the .env file via the install controller, potentially leading to code execution or security bypasses.

- **Severity:** High 8.1 (`CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:H`)
- **Exploited in the wild:** Not known
- **Login needed:** Not needed
- **Attackable:** Over the internet
- **Victim action needed:** Not needed
- **Fix available:** Yes
- **Published:** 8 Apr 2026
- **Updated:** 8 Apr 2026
- **Also known as:** GHSA-vfhx-5459-qhqh

## What is CVE-2026-39394?

CVE-2026-39394 is a high-severity vulnerability in ci4-cms-erp ci4ms, published on 8 Apr 2026. An attacker can exploit it over the internet without logging in, with no action from the victim.

### Official description

CI4MS is a CodeIgniter 4-based CMS skeleton that delivers a production-ready, modular architecture with RBAC authorization and theme support. Prior to 0.31.4.0, the Install::index() controller reads the host POST parameter without any validation and passes it directly into updateEnvSettings(), which writes it into the .env file via preg_replace(). Because newline characters in the value are not stripped, an attacker can inject arbitrary configuration directives into the .env file. The install routes have CSRF protection explicitly disabled, and the InstallFilter can be bypassed when cache('settings') is empty (cache expiry or fresh deployment). This vulnerability is fixed in 0.31.4.0.

Weakness: CWE-93 (Improper Neutralization of CRLF Sequences)

## Which versions are affected by CVE-2026-39394?

2 open source packages ship an affected version, including ci4-cms-erp/ci4ms. It affects 1 product.


| Package | Ecosystem | Affected | Fixed in |
| --- | --- | --- | --- |
| `ci4-cms-erp/ci4ms` | Packagist | All versions | 0.31.4.0 |
| `ci4-cms-erp/ci4ms` | Packagist | All versions | 0.31.4.0 |

Products: Ci4-Cms-Erp Ci4ms.

## How do I fix CVE-2026-39394?

Upgrade ci4-cms-erp/ci4ms to 0.31.4.0 or later.

## Is CVE-2026-39394 being exploited?

It is not confirmed as exploited in the wild, but public exploit code for CVE-2026-39394 exists.

## Other vulnerabilities in ci4-cms-erp ci4ms

- [CVE-2026-34569](https://insights.sbomify.com/CVE-2026-34569/): CI4MS: Blogs Categories Full Account Takeover for All-Roles & Privilege-Escalation via Stored DOM XSS (critical 10.0)
- [CVE-2026-34571](https://insights.sbomify.com/CVE-2026-34571/): CI4MS: Stored Cross‑Site Scripting (Stored XSS) in Backend User Management Allows Session Hijacking and Full Administrative Account Compromise (critical 10.0)
- [CVE-2026-25510](https://insights.sbomify.com/CVE-2026-25510/): CI4MS Vulnerable to Remote Code Execution (RCE) via Arbitrary File Creation and Save in File Editor (critical 10.0)
- [CVE-2026-34989](https://insights.sbomify.com/CVE-2026-34989/): CI4MS: Profile & User Management Full Account Takeover for All-Roles & Privilege-Escalation via Stored DOM XSS (critical 9.4)
- [CVE-2026-34559](https://insights.sbomify.com/CVE-2026-34559/): CI4MS: Blogs Tags Full Account Takeover for All-Roles & Privilege-Escalation via Stored DOM XSS (critical 9.1)

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2026-39394 and fix it if it is affected.

What it is: CVE-2026-39394 is a high-severity vulnerability in ci4-cms-erp ci4ms, published on 8 Apr 2026. An attacker can exploit it over the internet without logging in, with no action from the victim.
Exploitation: It is not confirmed as exploited in the wild, but public exploit code for CVE-2026-39394 exists.

Affected packages and fixed versions:
- ci4-cms-erp/ci4ms (Packagist): affected all versions; fixed in 0.31.4.0
- ci4-cms-erp/ci4ms (Packagist): affected all versions; fixed in 0.31.4.0

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-2026-39394/ (Markdown: https://insights.sbomify.com/CVE-2026-39394/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2026-39394
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-39394
- OSV: https://osv.dev/vulnerability/CVE-2026-39394

---
From sbomify Insights: https://insights.sbomify.com/CVE-2026-39394/
Summaries are generated and may contain mistakes; the official description above is the record.