CVE-2026-34565
CRITICAL9.1EPSS 0.05%CI4MS: Menu Management (Posts) Full Account Takeover for All-Roles & Privilege-Escalation via Stored DOM XSS
Description
## Summary ### **Vulnerability: Stored DOM XSS via Posts Added to Menu (Persistent Payload Injection)** - Stored Cross-Site Scripting via Unsafe Rendering of Post Entries in Menu Management ### Description The application fails to properly sanitize user-controlled input when **adding Posts to navigation menus** through the Menu Management functionality. Post-related data selected via the Posts section is stored server-side and rendered without proper output encoding. These stored values are later rendered unsafely within administrative dashboards and public-facing navigation menus, resulting in stored DOM-based cross-site scripting (XSS). ### Affected Functionality - Menu Management – Posts section - Adding posts to navigation menus - Menu storage and rendering logic ### Attack Scenario - An attacker creates or controls a post containing a malicious JavaScript payload. - The attacker adds the post to the menu using the **Posts** functionality in Menu Manager. - The application stores the menu entry without sanitization or encoding. - The payload persists and executes whenever the menu is rendered. ### Impact - Persistent Stored DOM XSS - Execution of arbitrary JavaScript in victims’ browsers - Privilege escalation in administrative contexts - Full administrator account takeover - Full account takeover across all roles - Full compromise of the entire application via global navigation execution Endpoint: - `/backend/menu/` ## Steps To Reproduce (POC) 1. Navigate to Menu Management 2. Use the **Posts** section to add a post containing an XSS payload such as: `<img src=x onerror=alert(document.domain)>` 3. Save the menu 4. View the menu in the administrative panel or any public-facing page 5. Observe the JavaScript payload executing automatically ## Remediation - **Avoid unsafe DOM manipulation methods:** Do not use `.html()`, `innerHTML`, or similar sink functions in client-side JavaScript or server-side templating (e.g., PHP). Even when user input flowing into these sinks is not immediately apparent, they can introduce Cross-Site Scripting (XSS) vulnerabilities that an attacker may exploit. - **Apply output encoding:** Implement HTML entity encoding on all user-controlled data before rendering it in the browser. This helps neutralize potentially malicious input. - **Implement input sanitization:** Ensure that all user-supplied input is properly sanitized before processing or output. Currently, no sanitization mechanisms are in place, which should be addressed as a priority. - **Enforce security headers and cookie attributes:** - **Content Security Policy (CSP):** Define and enforce a strict CSP to limit the execution of unauthorized scripts. - **HttpOnly flag:** Set the `HttpOnly` attribute on session cookies to prevent client-side script access. - **SameSite attribute:** Configure the `SameSite` cookie attribute to mitigate Cross-Site Request Forgery (CSRF) risks. - **Secure flag:** Ensure all cookies are transmitted only over HTTPS by enabling the `Secure` attribute. These measures collectively reduce the impact of XSS and help prevent escalation paths such as CSRF via XSS. # Ready Video POC: https://mega.nz/file/PcMiUA5K#L2RlZJa340Q8K42TksxiXMuo_9XsRYPi14-WvBnak2A
Affected packages (1)
- Packagist/ci4-cms-erp/ci4msfrom 0, < 0.31.0.0
CVSS scores
| Source | Version | Severity | Vector |
|---|---|---|---|
| osv | CVSS 3.1 | CRITICAL9.1 | CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:C/C:H/I:L/A:L |