CVE-2026-34567 CI4MS: Blogs Posts (Categories) Full Account Takeover for All-Roles & Privilege-Escalation via Stored DOM XSS

Critical 9.1 Published 1 Apr 2026 Updated 2 Apr 2026

Attackers can inject malicious scripts into blog categories to steal sessions and escalate privileges in CI4MS.

Exploited in the wild: Not known
Login needed: Any signed-in user
Attackable: Over the internet
Victim action needed: Not needed
Fix: Available

What is CVE-2026-34567?

CVE-2026-34567 is a critical cross-site scripting vulnerability in ci4-cms-erp ci4ms, published on 1 Apr 2026. Any signed-in user can exploit it over the network, with no action from the victim.

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 version 0.31.0.0, the application fails to properly sanitize user-controlled input when creating or editing blog posts within the Categories section. An attacker can inject a malicious JavaScript payload into the Categories content, which is then stored server-side. This stored payload is later rendered unsafely when the Categories are viewed via blog posts, without proper output encoding, leading to stored cross-site scripting (XSS). This issue has been patched in version 0.31.0.0.

Weakness: CWE-79

Which versions are affected by CVE-2026-34567?

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	`0.31.0.0`
`ci4-cms-erp/ci4ms` Packagist	All versions	`0.31.0.0`

Products include Ci4-Cms-Erp Ci4ms.

How do I fix CVE-2026-34567?

Upgrade ci4-cms-erp/ci4ms to 0.31.0.0 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-2026-34567 being exploited?

It is not confirmed as exploited in the wild, but public exploit code for CVE-2026-34567 exists.

Sources

Also known as GHSA-r33w-c82v-x5v7.