Vulnerability · Published Apr 8, 2026 · Assigned by GitHub_M

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

High 8.1

In plain English

A high-severity missing authentication in ci4ms from ci4-cms-erp. Proof-of-concept exploit code is public. The chance it is exploited in the next 30 days is estimated at 0.4% (higher than 37% of all known vulnerabilities). Fixed versions are available - upgrade the affected package.

Severity (CVSS 3.1)8.1High

Exploit odds (30 days)0.4%top 62.8% of all CVEs

Exploited in the wildNo reportsCISA SSVC: poc

Attack toolingNoneno public tooling known

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 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.

Affected packages & fixed versions

Ecosystem	Package	Fixed in	Advisory
Packagist	ci4-cms-erp/ci4ms	0.31.4.0	GHSA-8rh5-4mvx-xj7j

Affected products (as reported)

Vendor	Product	Versions
ci4-cms-erp	ci4ms	< 0.31.4.0

Weakness: CWE-306 · Vector: CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:H

References

https://github.com/ci4-cms-erp/ci4ms/security/advisories/GHSA-8rh5-4mvx-xj7j x_refsource_CONFIRM