GHSA-vxq6-8cwm-wj99 LibreNMS allows stored XSS in Alert Template name field

• Packagist librenms/librenms: < 25.8.0 → fixed in 25.8.0

Summary A stored Cross-Site Scripting (XSS) vulnerability exists in LibreNMS (alert(document.cookie)&lt;/script> ``` and filling the other fields with arbitrary content (e.g., `test`), once the template is saved, the script is executed. This confirms that user input is stored and later rendered without proper output encoding. This vulnerability can be exploited for session hijacking, data theft, or other malicious actions targeting other admin users. --- PoC 1. Log in to LibreNMS using an account with the admin role. 2. Navigate to: `http://localhost:8000/templates`. 3. Click the "Create new alert template" button. 4. Input the following into the Template name field: ``` &lt;script>alert(document.cookie)&lt;/script> ``` 5. Fill the remaining fields (`Template`, `Alert title`, `Recovery title`) with arbitrary content such as `test`. 6. Click "Create template". 7. Upon saving, a JavaScript alert pops up, confirming the stored XSS is triggered. --- Impact Type: Stored Cross-Site Scripting (XSS) Affected users: Only accounts with the admin role who access the Alert Templates page (`http://localhost:8000/templates`) are affected. Attackers need: Authenticated admin-level access.