CVE-2026-39391: CI4MS has Stored XSS via Unescaped Blacklist Note in Admin User List

Severity: medium (CVSS 4.8 v3.1)
Exploited in the wild: not listed in CISA KEV
EPSS: 0.2% probability of exploitation in the next 30 days
Public exploit or detection template: yes
Published: 2026-04-08 · updated 2026-07-20
Weakness: CWE-79

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 blacklist (ban) note parameter in UserController::ajax_blackList_post() is stored in the database without sanitization and rendered into an HTML data-note attribute without escaping. An admin with blacklist privileges can inject arbitrary JavaScript that executes in the browser of any other admin who views the user management page. This vulnerability is fixed in 0.31.4.0.

Affected products

ci4-cms-erp ci4ms: before 0.31.4.0 — fixed in 0.31.4.0

How to fix

Upgrade to a fixed version: ci4-cms-erp ci4ms 0.31.4.0. Check the vendor advisory for mitigations.

References

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