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 tags. An attacker can inject a malicious JavaScript payload into the tag name field, which is then stored server-side. This stored payload is later rendered unsafely across public tag pages and administrative interfaces 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 Tag Name (Persistent Payload Injection)** - Stored Cross-Site Scripting via Unsanitized Blog Tag Name in Blog Management

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

This stored payload is later rendered unsafely across public tag pages and administrative interfaces without proper output encoding, leading to stored cross-site scripting (XSS).

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

### Attack Scenario - An attacker creates or edits a blog tag name to include a malicious XSS payload. - The application stores this value without sanitization or encoding. - The payload persists and executes whenever the tag name 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/tags/` - `/blog/{id}`

## Steps To Reproduce (POC) 1. Go to the Blog Tags management page 2. Create or edit a tag and insert an XSS payload into the tag name such as: `<img src=x onerror=alert(do…