Authenticated Contributor Stored XSS in “Anber Elementor Addon” (<= 1.0.1) — What Site Owners and Developers Must Do Today

Published: 16 August 2025  |  Author: Hong Kong Security Expert

Summary

A stored cross-site scripting (XSS) vulnerability (CVE-2025-7440) has been identified in the Anber Elementor Addon plugin (versions ≤ 1.0.1). An authenticated user with Contributor privileges can inject JavaScript into a carousel button link value that is stored persistently and executes in visitors’ browsers when the carousel is viewed. This allows client-side attacks such as session theft, silent redirections, injection of malicious content, and actions performed in the context of the site.

At the time of writing there is no official plugin update that fully remediates the issue for the affected versions. The guidance below is practical, prioritised, and written for site owners and developers who need to act immediately — whether you manage a single site or a fleet.

This advisory is issued from the perspective of a Hong Kong security practitioner with hands-on experience managing WordPress incident response and hardening.

Quick facts

• Affected plugin: Anber Elementor Addon
• Vulnerable versions: ≤ 1.0.1
• Vulnerability type: Stored Cross‑Site Scripting (XSS)
• Privilege required: Contributor (authenticated)
• CVE: CVE-2025-7440
• Reported: 16 Aug 2025
• Official patch: Not available (at time of writing)
• Practical impact: Arbitrary JavaScript execution in visitors’ browsers when they view an affected carousel element

Why this matters — short technical explanation

Stored XSS happens when untrusted content (HTML/JavaScript) is saved to a persistent storage location (database, postmeta, widget settings) and later rendered into pages without proper escaping or sanitisation.

In this case, the plugin exposes a button link field in a carousel widget. The plugin fails to validate and escape that input properly, allowing a Contributor to save a crafted value containing executable script or dangerous URL schemes. When a visitor or an authenticated user views the page with that carousel, the payload executes in the context of the site.

Because the payload is served from the site’s own origin, it inherits same-origin privileges in the browser (cookies, local storage, DOM access), making stored XSS particularly impactful.

Who is at risk?

• Sites running the vulnerable plugin version (≤ 1.0.1) that use the carousel widget on any page.
• Sites that allow Contributor accounts (or similar low-privileged accounts) to create or edit content that includes Elementor widgets or to access the plugin’s widget UI.
• Visitors, editors, and administrators — depending on where the carousel appears and who views it.

Contributor privileges are frequently granted on community blogs and publications. Where Contributors can insert or edit content that references page-builder widgets or templates, the risk is real.

Realistic attack scenarios

• A malicious Contributor creates a post or template containing the vulnerable carousel and injects a payload into the button link field. Every visitor to that page receives the malicious script.
• The script silently redirects visitors to phishing domains, injects overlays to capture credentials, or drops a drive-by loader.
• The script exfiltrates session cookies or tokens for logged-in users to an attacker-controlled endpoint.
• The script performs privileged actions in the browser on behalf of an authenticated user (if CSRF protections are weak or absent).
• The attacker uses the carousel to display malicious ads or monetise the compromise.

Stored vulnerabilities require only a single successful injection; impact scales with traffic.

Immediate mitigations — prioritised steps for site owners (apply now)

If you run a WordPress site with this plugin, apply the following steps in order:

1. Inventory and isolation

• Confirm whether the plugin is installed and its version. In WP‑admin: Plugins → Installed Plugins and check Anber Elementor Addon.
• If installed and version ≤ 1.0.1, assume exposure and move to containment.

2. Reduce attack surface (fast, reversible)

• Temporarily deactivate the plugin until a safe update exists. Deactivation is the simplest low-risk action.
• If you cannot deactivate immediately because the site depends on it, restrict or remove Contributor capabilities:
  • Convert Contributor accounts to Subscriber or suspend them temporarily.
  • Introduce a review/publishing workflow so unreviewed content cannot be published or used in templates.
• If your site allows registration with Contributor as default, disable new registrations or set default role to Subscriber.

3. Block the vector with a WAF or request filtering (temporary)

Where possible, implement request filtering at the edge (reverse proxy, web server, or plugin-based filtering) to block obvious exploit attempts. Example checks:

• Block POSTs that include suspicious patterns for widget fields, such as <script, javascript:, onerror=, onload= or other inline event handlers in values intended to be URLs.
• Inspect POST parameters used to save widget settings and block values containing HTML tags.

Note: server-side request filtering is a temporary mitigation to reduce exposure while you perform cleanup and await an upstream fix.

4. Search and remove existing stored payloads

Search post content and widget settings in wp_posts (post_content) and wp_postmeta (meta_value) for suspicious script tags and JavaScript URIs, then remove or sanitise any confirmed malicious entries.

Example WP‑CLI / SQL queries (run only after taking a full backup):

wp db query "SELECT post_id, meta_key, meta_value FROM wp_postmeta WHERE meta_value LIKE '%<script%';"
wp db query "SELECT ID, post_title FROM wp_posts WHERE post_content LIKE '%<script%';"
wp db query "SELECT ID, post_title FROM wp_posts WHERE post_content LIKE '%javascript:%';"

If unsure about an item, export the raw content offline for analysis, then remove the suspicious entry from the live site.

5. Audit recent changes by Contributor accounts

• Query for posts, templates, or reusable blocks recently created/edited by Contributor users and inspect Elementor content for injected values.
• Suspend or lock suspicious accounts pending investigation.

6. Monitor and scan

• Run a malware scan across site files and the database. Look for unexpected admin users, uploaded files in wp-content/uploads, or modified core/plugin/theme files.
• Review web server logs for unusual POSTs and any outgoing connections to unfamiliar domains.

7. Communication and rollback plan

• If you confirm a compromise: put the site into maintenance mode, take a full forensic backup (files + DB), and restore from a known-good backup when appropriate.
• Rotate credentials for Administrator/Editor accounts and any API keys that may have been exposed.

How to detect if your site has been exploited

• Pages that include embedded <script> tags within carousel areas, button links containing javascript: URIs, or elements with onerror attributes in image or link HTML.
• Browser console errors or unexpected redirects when visiting carousel pages.
• Web access logs showing POSTs that submit HTML or javascript: URIs to endpoints used by the page builder or plugin.
• Outgoing requests from the server to attacker domains indicating data exfiltration.
• Recently added or modified content by Contributor accounts that looks suspicious.

Combine DB content checks, user audits, and log analysis for thorough detection.

Cleaning up stored XSS safely

1. Create a full site backup (files + database) and preserve it offline for investigation.
2. Use the DB queries above to find injected content and export suspicious entries for offline review.
3. Sanitise or remove malicious meta values and post content. Replace injected HTML with safe placeholders or remove the widget instance entirely.
4. Rotate passwords and expire sessions for users who may have viewed or edited pages while the payload was present.
5. Re-scan the site after cleanup and re-enable the plugin only when you are confident there is no remaining stored content.
6. If unsure, restore from a backup taken before the injection and then apply compensating controls (request filtering, role hardening) before reintroducing user content.

For multiple sites, automate scanning of postmeta for script markers and escalate findings for manual review.

Developer guidance — how to fix the plugin code (high level)

If you maintain code that handles user input for widget link fields, apply these secure coding practices:

• Sanitise on input and escape on output:
  • Use esc_url_raw() when storing URLs.
  • Validate URLs with wp_http_validate_url() or parse_url() to allow only safe schemes (http, https, mailto if required).
  • When outputting into HTML attributes, use esc_attr() and esc_url() appropriately.
  • If limited HTML is required, whitelist tags using wp_kses() with a strict allowed list.
• Capability checks: verify current_user_can() for the correct capability before saving or rendering content in admin templates.
• Avoid storing raw HTML or script in link fields — treat link fields as plain text/URL and validate accordingly.
• Reject or sanitise javascript: and data: URIs on input — allow only http and https by default.
• Add server-side validation for all widget settings submitted via AJAX or form POSTs.

Conceptual pseudo-patch (illustrative)

// On save
$link_raw = isset( $data['button_link'] ) ? $data['button_link'] : '';
if ( ! empty( $link_raw ) ) {
    $link = esc_url_raw( $link_raw );
    if ( ! wp_http_validate_url( $link ) ) {
        $link = '';
    }
}
// store $link (not $link_raw)

// On render
echo '<a href="' . esc_url( $link ) . '" rel="noopener noreferrer">' . esc_html( $button_text ) . '</a>';

This approach stores only validated URLs and ensures correct escaping at render time.

Request filtering rule examples (conceptual, non-executable guidance)

Temporary request filters can buy time while a code fix is prepared. Keep rules precise to reduce false positives. High-level checks:

• Block POSTs to widget save endpoints that include <script or onerror in values intended to be URLs.
• Block values for link fields that contain the javascript: or data: schemes.
• Flag (log + hold) admin AJAX requests that contain HTML tags in URL fields for manual review.

Hardening checklist for site owners

• Limit roles and capabilities: avoid giving Contributor accounts access to page builders or template editors.
• Enforce content moderation: require Author/Editor review before page-builder content goes live.
• Keep WordPress core, themes, and plugins up to date and apply security patches promptly.
• Consider a Content Security Policy (CSP) to reduce impact of injected scripts (CSP can block inline script execution and external script loads when configured correctly).
• Use HTTP security headers: CSP, X-Content-Type-Options, X-Frame-Options, Referrer-Policy.
• Regularly scan posts and postmeta for unexpected HTML tags or javascript: URIs.
• Maintain activity logging (user actions, page publications) and monitor for atypical behaviour.

For hosts and agencies — operational response at scale

• Run automated scans across client databases to search for <script occurrences in postmeta and post_content.
• Implement global request filters that block obvious stored XSS payloads on page-builder endpoints, with per-site tuning.
• Notify affected clients promptly and provide clear remediation steps.
• Offer emergency hardening services: temporarily suspend the vulnerable plugin across clients or apply virtual patches at the edge until vendor fixes are available.
• Perform role audits to prevent low-trust contributors from accessing page-builder editing capabilities.

Why stored XSS from low‑privileged users is dangerous

Operators often presume Contributors are harmless because they cannot publish. However, where page-builder widgets, reusable blocks, templates, or editor flows allow Contributors to insert content that later gets rendered to visitors (or viewed by administrators), the ability to persist JavaScript into widget settings can grant attackers a persistent foothold.

A single stored injection can affect every visitor, including administrators who view the page while logged in, exposing session tokens and admin UX to compromise.

Short recommendations

1. If the plugin is present and version ≤ 1.0.1, assume exposure and take containment steps immediately.
2. Deactivate the plugin or restrict Contributor access until a verified fix is available.
3. Scan the database for <script and javascript: URIs in postmeta and post_content and remove malicious content.
4. Use temporary request filtering at the edge while cleaning the site and awaiting an upstream patch.
5. Developers should enforce strict input validation and escaping: sanitise on input and escape on output; disallow dangerous schemes in link fields.

Final notes and resources

Treat this vulnerability seriously if you host user-generated content or allow Contributors to interact with page-builder widgets. Immediate mitigation is feasible and should be prioritised: plugin deactivation or role restriction combined with database cleanup and request filtering will prevent further exploitation while you work toward a full fix.

Monitor the plugin author’s channels for an official security release. When an official update is published, review it on a staging environment first and validate the fix before rolling to production.

If you would like a step-by-step checklist exported for your team (including exact WP‑CLI queries and sample request-filter templates), request a downloadable remediation playbook and include details about your hosting environment so it can be tailored to your setup.

Disclosure: This advisory is provided for informational and remediation purposes. Follow your organisation’s incident response processes and regulatory obligations when handling potential compromises.