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. An attacker can inject a malicious JavaScript payload into blog post content, which is then stored server-side. This stored payload is later rendered unsafely in multiple application views without proper output encoding, leading to stored cross-site scripting (XSS). This issue has been patched in version 0.31.0.0.

Affected: Packagist: ci4-cms-erp/ci4ms

## Summary ### **Vulnerability: Stored DOM XSS via Blog Post Content (Persistent Payload Injection)** - Stored Cross-Site Scripting via Unsanitized Blog Post Content in Blog Management

### Description The application fails to properly sanitize user-controlled input when creating or editing blog posts. An attacker can inject a malicious JavaScript payload into blog post content, which is then stored server-side.

This stored payload is later rendered unsafely in multiple application views without proper output encoding, leading to stored cross-site scripting (XSS).

### Affected Functionality - Blog post creation functionality - Blog post editing functionality - Blog post storage and retrieval logic

### Attack Scenario - An attacker creates or edits a blog post to include a malicious XSS payload. - The application stores this content without sanitization or encoding. - The payload persists and executes whenever the blog post is rendered in affected views.

### Impact - Persistent Stored XSS - Execution of arbitrary JavaScript in victims’ browsers - Privilege escalation when viewed by administrators or privileged users - Full administrator account takeover - Full account takeover across all roles - Full compromise of the entire application

Endpoints: - `/backend/blogs/create` - `/backend/blogs/` - `/blog/{id}`

## Steps To Reproduce (POC) 1. Go to the Blog Post Create or Edit page 2. Insert an XSS payload into the blog post content such as: `<img src=x onerror=alert(documen…