CVE-2026-39391 CI4MS has Stored XSS via Unescaped Blacklist Note in Admin User List
An admin can inject JavaScript via blacklist notes that executes in other admins' browsers, potentially leading to account takeover.
- Exploited in the wild
- Not known
- Login needed
- An administrator
- Attackable
- Over the internet
- Victim action needed
- A user has to click or open something
- Fix
- Available
What is CVE-2026-39391?
CVE-2026-39391 is a medium-severity cross-site scripting vulnerability in ci4-cms-erp ci4ms, published on 8 Apr 2026. An attacker needs administrator access to exploit it, and only if a user opens a file or follows a link.
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 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.
Weakness: CWE-79
Which versions are affected by CVE-2026-39391?
2 open source packages ship an affected version, including ci4-cms-erp/ci4ms. It affects 1 product.
| Package | 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 include Ci4-Cms-Erp Ci4ms.
How do I fix CVE-2026-39391?
Upgrade ci4-cms-erp/ci4ms to 0.31.4.0 or later.
Escape output for the context it lands in and set a strict Content Security Policy. Upgrading the affected component is the real fix. More about Cross-site scripting.
Is CVE-2026-39391 being exploited?
It is not confirmed as exploited in the wild, but public exploit code for CVE-2026-39391 exists.
Other vulnerabilities in ci4-cms-erp ci4ms
- CVE-2026-34569 CI4MS: Blogs Categories Full Account Takeover for All-Roles & Privilege-Escalation via Stored DOM XSS
- CVE-2026-34571 CI4MS: Stored Cross‑Site Scripting (Stored XSS) in Backend User Management Allows Session Hijacking and Full Administrative Account Compromise
- CVE-2026-25510 CI4MS Vulnerable to Remote Code Execution (RCE) via Arbitrary File Creation and Save in File Editor
- CVE-2026-34989 CI4MS: Profile & User Management Full Account Takeover for All-Roles & Privilege-Escalation via Stored DOM XSS
- CVE-2026-34559 CI4MS: Blogs Tags Full Account Takeover for All-Roles & Privilege-Escalation via Stored DOM XSS
Sources
Also known as GHSA-7cm9-v848-cfh2.