CVE-2026-34557 CI4MS: Permissions Management Full Account Takeover for All-Roles & Privilege-Escalation via Stored DOM XSS

Critical 9.1 Published 30 Mar 2026 Updated 31 Mar 2026

Attackers can inject malicious scripts into role management fields, leading to stored XSS that enables full account takeover and privilege escalation for administrators.

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-2026-34557?

CVE-2026-34557 is a critical cross-site scripting vulnerability in ci4-cms-erp ci4ms, published on 30 Mar 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 within group and role management functionality. Multiple input fields (three distinct group-related fields) can be injected with malicious JavaScript payloads, which are then stored server-side. These stored payloads are later rendered unsafely within privileged administrative views without proper output encoding, leading to stored cross-site scripting (XSS) within the role and permission management context. This issue has been patched in version 0.31.0.0.

Weakness: CWE-79

Which versions are affected by CVE-2026-34557?

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-2026-34557?

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-2026-34557 being exploited?

It is not confirmed as exploited in the wild, but public exploit code for CVE-2026-34557 exists.

Sources

Also known as GHSA-rpjr-985c-qhvm.