اسم البرنامج الإضافي	Add User Meta
Type of Vulnerability	CSRF and Stored XSS
CVE Number	CVE-2025-7688
الاستعجال	واسطة
CVE Publish Date	2025-08-15
Source URL	CVE-2025-7688

Urgent Security Advisory: Add User Meta plugin (≤ 1.0.1) — CSRF → Stored XSS (CVE-2025-7688)

تاريخ: 15 August 2025
مؤلف: WP-Firewall Security Team

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ملخص

• وهن: Cross-Site Request Forgery (CSRF) enabling Stored Cross-Site Scripting (XSS)
• Affected software: Add User Meta WordPress plugin, versions ≤ 1.0.1
• CVE: CVE-2025-7688
• Privilege required: Unauthenticated (attacker may exploit from the web)
• Public fix: None available at time of disclosure
• WP-Firewall recommendation: Mitigate immediately — remove or disable the plugin, apply virtual patching via your WAF, and follow the incident response checklist below.

This advisory explains the technical details, exploitation scenarios, detection and containment processes, code-level fixes for plugin authors, virtual patch/WAF rules you can deploy immediately, and longer-term hardening to avoid similar issues in future.

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What happened (short)

The Add User Meta plugin exposes an endpoint or action that allows adding or updating user metadata without proper CSRF protections and without validating or sanitizing input. Because there’s no effective nonce/CSRF check and user-provided data is stored and output without safe escaping, an attacker can craft a request (or trick an authenticated user to submit one) that persists script-based payloads into user meta fields. Those payloads subsequently render in pages or admin views where the meta values are echoed, resulting in stored XSS.

Because the issue is exploitable by unauthenticated attackers, the risk is higher than usual: attackers may be able to inject persistent payloads that affect admins or site visitors.

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Why this is serious

Stored XSS is among the most dangerous client-side vulnerabilities on web platforms like WordPress:

• Persistent execution: malicious JavaScript is stored on the server and executes whenever the vulnerable page is viewed.
• Admin compromise: if an admin views a page or user profile or interacts with the WP admin UI that outputs the unsafe meta, an attacker can hijack an admin session (cookie theft, privilege escalation) or create admin-level changes.
• Reputation and SEO damage: injected content can be used to inject spam, ads, or phishing content that damages trust and search rankings.
• Automated exploitation: public disclosure often leads to automated scans and mass exploitation; immediate mitigation is critical.

CVSS and priority: this issue has a CVSS-like assessment around 7.1 (medium/high). Because it’s unauthenticated and persistent, we treat it as actionable and advise immediate mitigation.

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Technical analysis

Root causes typically present in this kind of plugin vulnerability:

1. Missing CSRF protection (no nonce / no check_admin_referer / wp_verify_nonce)
2. Allowing unauthenticated or insufficiently authorized requests to write to user meta
3. Lack of input validation (accepting arbitrary HTML or script payloads)
4. Unsafe output (echoing meta value without esc_html(), esc_attr(), or wp_kses())

Typical vulnerable flow:

• Plugin registers an AJAX or form endpoint (possibly front-end) that accepts parameters: user_id, meta_key, meta_value.
• The endpoint processes input and writes directly to wp_usermeta via add_user_meta() / update_user_meta() without verifying origin or sanitizing meta_value.
• Later, the plugin (or other theme/plugin code) outputs that meta value in HTML without escaping, letting <script> tags or event handlers execute.

Important exploitation notes:

• If endpoint accepts POSTs from unauthenticated clients, attacker-hosted pages can issue POSTs (CSRF) to store payloads.
• Even if the endpoint requires cookies, a CSRF request can be crafted to run in the context of a logged-in administrator (social engineering) — but this specific report indicates the vulnerability can be exploited unauthenticated.
• Stored XSS payloads may be triggered in admin interfaces (profile pages, user list), front-end author pages, or any place where the value is rendered.

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Immediate actions — for site owners / operators

If you run WordPress sites and use the Add User Meta plugin (≤1.0.1), follow these steps immediately:

1. Take a hot backup (files + database).
2. Disable or remove the plugin immediately if you can (remove from Plugins page, or delete plugin folder via SFTP). Removing the plugin prevents the endpoint from receiving new malicious input.
3. If removal is not possible at the moment, block access to the plugin’s endpoints via your firewall (WAF, server firewall, .htaccess) — see WAF rules below to virtual patch.
4. Scan your database for suspicious values in the wp_usermeta table:
   • Run queries to find script tags or event handlers saved in meta_value.
   • Example SQL to search:

   SELECT user_id, meta_key, meta_value
   FROM wp_usermeta
   WHERE meta_value LIKE '%<script%'
      OR meta_value LIKE '%javascript:%'
      OR meta_value LIKE '%onerror=%'
      OR meta_value LIKE '%onload=%';
       

5. Check logs for suspicious POST requests or requests to plugin-specific URIs and for unusual User-Agent strings:
   • Look for POSTs with suspicious payloads or large amounts of data to the plugin endpoints.
6. If you find injected script payloads, isolate affected entries:
   • Remove or sanitize immediately (by replacing payload with a safe value or null).
   • If admin accounts are suspected to be compromised (weird admin changes, new admins), rotate passwords and invalidate sessions.
7. Reset credentials for high-privilege accounts and revoke API keys that may have been exposed.
8. Run a full malware scan and search for other indicators of compromise (webshells, modified core/plugin files).
9. Notify stakeholders and, if needed, restore from a clean backup from before the compromise.

Note: If you are not confident performing response steps yourself, contact your host or a professional incident response service.

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Detection indicators (IoCs)

Look for:

• Usermeta entries containing <script>, javascript:, onerror=, onload=.

SELECT user_id, meta_key, meta_value
FROM wp_usermeta
WHERE lower(meta_value) REGEXP '<script|onerror|onload|javascript:|document.cookie|alert\(';'

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Virtual patch / WAF mitigations you can apply immediately

If you run WP-Firewall or any WAF, apply virtual patch rules to mitigate exploitation while a full plugin fix is unavailable.

Suggested WAF rule categories:

1. Block/inspect requests that attempt to write usermeta:
   • Block POST requests to known plugin endpoints or any requests containing suspicious parameter names (meta_key, meta_value, add_usermeta, modify_user_meta).
2. Block inputs containing script patterns:
   • If a POST contains <script, javascript:, onerror=, onload=, ملف تعريف الارتباط، أو تقييم(, block or challenge (CAPTCHA).
3. Enforce same-origin / CSRF protections:
   • Reject POSTs with missing or invalid Referer or Origin headers for endpoints that should be same-origin only.
4. Rate-limit unauthenticated POSTs to endpoints that modify data.

Example ModSecurity rule (conceptual — adapt to your engine and test before use):

# Block attempts to inject <script> or event handlers in POST bodies
SecRule REQUEST_METHOD "POST" "chain,deny,status:403,log,msg:'Blocked potential stored XSS payload in POST body'"
  SecRule REQUEST_BODY "(?i)(<script|javascript:|onerror=|onload=|document\.cookie|eval\()" "t:none,t:urlDecode"

Example nginx + Lua or server rule (simple):

if ($request_method = POST) {
    set $bad_payload 0;
    if ($request_body ~* "<script") { set $bad_payload 1; }
    if ($request_body ~* "document.cookie") { set $bad_payload 1; }
    if ($bad_payload = 1) {
        return 403;
    }
}

Example WordPress-specific WAF rule (conceptual):

• Block requests where POST contains parameter names meta_key أو meta_value from unauthenticated sessions:

  if POST contains 'meta_key' or 'meta_value' and user not authenticated:
     block / challenge
      

Be careful: overly broad rules can break legitimate functionality. Start by blocking high-confidence malicious patterns (script tags and event handlers) and then refine.

WP-Firewall customers: we’ve already logged this vulnerability and can enable virtual patching rules that match the patterns above. If you’re on our managed plan we push these rules proactively. (See signup paragraph at the end.)

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Secure coding fixes for plugin authors

If you are a plugin developer or maintain the affected plugin, implement these code-level changes:

1. Enforce CSRF protection:
   • For forms and AJAX endpoints that change data, require and verify nonces.
   • For admin-side changes, use check_admin_referer() أو wp_verify_nonce().
   • مثال:

     if ( ! isset( $_POST['my_plugin_nonce'] ) || ! wp_verify_nonce( $_POST['my_plugin_nonce'], 'my_plugin_action' ) ) {
         wp_die( 'Invalid request' );
     }
             

2. Require authentication and minimal capability:

   if ( ! current_user_can( 'edit_users' ) ) {
       wp_die( 'Insufficient permissions' );
   }
       

3. Whitelist allowed meta keys:

   $allowed_keys = array( 'twitter_handle', 'job_title' );
   if ( ! in_array( $meta_key, $allowed_keys, true ) ) {
       wp_die( 'Invalid meta key' );
   }
       

4. Sanitize input before storing:
   • If you expect plain text: use تطهير حقل النص.
   • If you allow limited HTML: use wp_kses() with an allowed tags array.
   • مثال:

     $value = isset( $_POST['meta_value'] ) ? wp_kses_post( $_POST['meta_value'] ) : '';
     update_user_meta( $user_id, $meta_key, $value );
             

5. Escape output where user meta is printed:

   echo esc_html( get_user_meta( $user_id, 'job_title', true ) );
       

6. Avoid writing raw HTML into database unless absolutely required and validated.
7. Log suspicious attempts and provide admin notifications when malformed input is blocked.

Adopting these fixes will eliminate the chain that leads from CSRF to stored XSS.

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Incident Response Checklist (detailed)

1. Containment
   • Disable/remove the vulnerable plugin.
   • Block the relevant endpoints at the webserver/WAF level.
2. Preservation
   • Export logs and database snapshots (do not overwrite).
3. Discovery
   • Search wp_usermeta for malicious entries (see SQL above).
   • Review access logs and error logs for suspicious POSTs.
   • Look for indicators of admin session takeover or automated attacks (sudden changes in user roles, new admin accounts).
4. Eradication
   • Remove malicious meta entries and any webshells or unexpected files.
   • Patch or delete the vulnerable plugin.
   • Rotate admin user passwords and API credentials; invalidate all sessions (WordPress: use Tools > Export sessions or custom code to destroy sessions).
   • Run integrity checks of core, themes, plugins.
5. استعادة
   • Restore from a clean backup if needed.
   • Re-run malware scans and re-enable site features systematically.
6. Lessons learned
   • Review security monitoring, make WAF rules permanent where appropriate, enable automated alerts for similar patterns.

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Long-term hardening and monitoring

• Use a managed Web Application Firewall to automatically block patterns used by XSS/CSRF exploitation.
• Enforce Content Security Policy (CSP) to reduce damage from injected scripts:

  Content-Security-Policy: default-src 'self'; script-src 'self' 'nonce-...'; object-src 'none'; base-uri 'self';
      

  CSP is not a substitute for secure code but reduces attack surface.

• Set cookies with HttpOnly and Secure flags to limit theft via JS:
  • WordPress sets cookies by default; ensure your host uses HTTPS and secure cookie settings.
• Periodic plugin and code audits, and automatic vulnerability scanning of installed plugins.
• Harden admin area:
  • Limit admin login IPs if possible.
  • Use two-factor authentication for high-privilege accounts.
• Implement robust logging and alerting for suspicious POSTs and database changes.

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Practical WAF rule examples (conceptual — customize & test)

1. Detect and block script injection strings in POST bodies (ModSecurity format):

   SecRule REQUEST_METHOD "POST" "chain,deny,status:403,log,msg:'Possible stored XSS attempt (script tag) in POST'"
     SecRule REQUEST_BODY "(?i)<\s*script|\bonerror=|\bonload=|javascript:|document\.cookie|eval\(" "t:none,t:urlDecode"
       

2. Block requests attempting to write meta fields from unauthenticated clients (pseudo-rule):

   If REQUEST_METHOD == POST AND (REQUEST_BODY contains 'meta_key' OR 'meta_value' OR 'add_usermeta') AND user not authenticated:
       block
       

3. Enforce minimal content length for meta updates (reduce noise):
   • Many attacks include long payloads; block or challenge unusually large POST bodies to meta endpoints.

Caveat: Test rules in monitoring/log-only mode before dropping into blocking. Rules must be tuned to avoid false positives that break legitimate plugin functionality.

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Example: safe reimplementation for plugin authors (snippet)

This is a simplified safe endpoint handler. Use it as a starting point and adapt to your plugin architecture.

<?php
add_action( 'admin_post_myplugin_save_usermeta', 'myplugin_save_usermeta' );

function myplugin_save_usermeta() {
    // Verify nonce and referer
    if ( ! isset( $_POST['myplugin_nonce'] ) || ! wp_verify_nonce( $_POST['myplugin_nonce'], 'myplugin_save_usermeta_action' ) ) {
        wp_die( 'Invalid request' );
    }

    // Verify capability
    if ( ! current_user_can( 'edit_users' ) ) {
        wp_die( 'Insufficient permissions' );
    }

    $user_id = isset( $_POST['user_id'] ) ? intval( $_POST['user_id'] ) : 0;
    $meta_key = isset( $_POST['meta_key'] ) ? sanitize_key( $_POST['meta_key'] ) : '';
    $meta_value = isset( $_POST['meta_value'] ) ? sanitize_text_field( wp_unslash( $_POST['meta_value'] ) ) : '';

    // Whitelist allowed keys
    $allowed_keys = array( 'job_title', 'twitter_handle' );
    if ( ! in_array( $meta_key, $allowed_keys, true ) ) {
        wp_die( 'Invalid meta key' );
    }

    update_user_meta( $user_id, $meta_key, $meta_value );

    wp_safe_redirect( wp_get_referer() ? wp_get_referer() : admin_url() );
    exit;
}

When outputting:

echo esc_html( get_user_meta( $user_id, 'job_title', true ) );

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Exploitation scenarios (what an attacker could do)

• Inject a script into a user’s display name or bio meta, catching admin views of user profiles; use the admin user view to execute payload that changes settings or creates new admin users.
• Steal authentication cookies via script and send to attacker-controlled server.
• Inject persistent spam or phishing content on author pages indexed by search engines.
• Use XSS to pivot and run further attacks: CSRF to admin endpoints, remote code execution via other chained vulnerabilities, or install backdoors.

Because the vulnerability is unauthenticated in some configurations, attack surface is broad. Immediate mitigation is recommended.

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Do not wait for an official patch

Because there is no official fix at the time of disclosure, and because exploitation can be automated, do not wait to act. The combination of unauthenticated write and stored XSS is commonly weaponized quickly after disclosures are public.

Immediate options (in order of preference):

1. Remove or disable the vulnerable plugin (best).
2. If you cannot remove it, configure a virtual patch/WAF rule to block malicious payloads targeting the plugin.
3. Monitor and sanitize the wp_usermeta table for signs of injection, and rotate credentials if you see suspicious activity.

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Why virtual patching matters

Virtual patching with a WAF (managed rules on the edge) stops attacks at the HTTP layer before they hit the application. It provides:

• Immediate protection even if no vendor patch exists
• Low risk: does not change application code
• Rapid deployment: rules can be tuned and pushed across many sites quickly

WP-Firewall can provision targeted rules specific to this vulnerability to protect sites while you remove or replace the plugin.

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Practical examples for site operators

• If you host dozens or hundreds of WordPress sites, enable WAF rules that:
  • Block POSTs with <script> in body to endpoints that update meta
  • Enforce Referer header checks for sensitive endpoints
  • Rate-limit POSTs to admin-ajax and REST endpoints
• Add scheduled database scans for script-like patterns in wp_usermeta and alert on findings.
• Combine WAF blocking with security scanners to detect both known and unknown injection patterns.

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Final recommendations and next steps

1. Remove the Add User Meta plugin immediately (if installed).
2. If removal isn’t possible, apply WAF rule(s) to block script-based payloads and POSTs to the plugin’s endpoints.
3. Search and scrub the wp_usermeta table for persistent payloads.
4. Rotate admin accounts and any secrets that could be compromised.
5. Monitor logs and enable alerts for repeated POST attempts.
6. For plugin authors: implement CSRF protection, capability checks, input sanitization, output escaping, and whitelisting.

Taking these steps will greatly reduce the risk of lasting compromise from stored XSS attacks.

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If you need help applying any rules, interpreting logs, or running the recommended searches and cleanups, our WP-Firewall security team can assist. We can push virtual patches to block exploit traffic rapidly and help guide incident response. Stay safe — act now.