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Home / Blog / wordpress 4.0
Security Advisory

WordPress 4.0 Security: 235 CVEs & Critical Vulnerabilities

📅 June 07, 2026 ·⏱ 5 min read ·🔒 SiteRecipe Security Team
50 websites still running wordpress 4.0  → View full list
235
Total
12
Critical
50
High
167
Medium
6
Low

WordPress 4.0 is an outdated version running on approximately 50 websites worldwide, but it carries significant security risks that could compromise your data and visitors' safety. With 235 documented vulnerabilities—including 12 critical-level flaws—this older version is a prime target for hackers seeking unpatched entry points into websites. If your site still runs WordPress 4.0, understanding these risks and taking immediate action is essential for protecting your digital assets.

The vulnerabilities range from Remote Code Execution (RCE) attacks that allow attackers to take complete control of your site, to SQL injection exploits that expose your entire database. Several critical vulnerabilities exist in popular plugins commonly used with this WordPress version, including the Widget Options plugin and authentication solutions. This comprehensive guide will help you identify whether your site is vulnerable and provide actionable steps to secure it.

What is Wordpress 4.0?

WordPress 4.0 is an older major release of WordPress, the content management system powering over 40% of all websites on the internet. Released in 2014, WordPress 4.0 introduced significant improvements to the editing experience and overall platform stability at that time. However, like all software, WordPress receives regular security updates to patch newly discovered vulnerabilities—and version 4.0 stopped receiving official security support years ago.

When WordPress versions reach end-of-life, they no longer receive security patches or updates from Automattic (the company behind WordPress). This means any vulnerabilities discovered after support ends remain unfixed on those versions. Website owners running WordPress 4.0 are essentially operating with a ticking time bomb: every new vulnerability discovered in the core software or popular plugins becomes a permanent weakness on their site. This is why cybersecurity experts universally recommend upgrading to the latest stable WordPress version as quickly as possible.

Key Vulnerabilities in Wordpress 4.0

235 CVEs found. The most critical are explained below.

CRITICAL CVE-2024-8672 9.9/10 · CVSS v3.1 ⏱ Immediate
Widget Options Plugin - Hackers Can Run Commands

The Widget Options plugin has a serious flaw that lets attackers insert harmful code into your website. This happens through the display logic feature that works with page builders. If you're using this plugin version 4.0.7 or older, hackers can take complete control of your site.

Impact: An attacker could steal your data, modify your website content, create fake admin accounts, or use your site to attack visitors. Your website could go offline or be used to spread malware.

↗ View on NVD
CRITICAL CVE-2018-12534 9.8/10 · CVSS v3.0 ⏱ Immediate
Quick Chat Plugin - Database Can Be Accessed

The Quick Chat plugin before version 4.00 has a database vulnerability. Attackers can write malicious code that tricks the database into revealing or deleting sensitive information stored in your WordPress site.

Impact: Hackers could access customer data, passwords, emails, and other confidential information from your database. They could also delete or corrupt your website's data.

↗ View on NVD
CRITICAL CVE-2016-10887 9.8/10 · CVSS v3.0 ⏱ Immediate
Security Plugin - Multiple Database Vulnerabilities

The All-in-One WP Security & Firewall plugin before version 4.0.9 has multiple database security flaws. Despite being a security tool, it actually opens the door for attackers to access your database directly.

Impact: Your website's entire database could be exposed, including user accounts, passwords, and all stored information. Attackers could modify or delete critical data.

↗ View on NVD
CRITICAL CVE-2016-10888 9.8/10 · CVSS v3.0 ⏱ Immediate
Security Plugin - Multiple Database Vulnerabilities

The All-in-One WP Security & Firewall plugin before version 4.0.7 contains multiple flaws that compromise database security. Ironically, this security plugin creates vulnerabilities rather than preventing them.

Impact: Your database containing all website and customer data becomes accessible to attackers. They can steal, modify, or destroy your information.

↗ View on NVD
CRITICAL CVE-2019-15780 9.8/10 · CVSS v3.1 ⏱ Immediate
Formidable Plugin - Unsafe Data Processing

The Formidable plugin before version 4.02.01 improperly handles serialized data (a way of storing information). Attackers can exploit this by injecting malicious code that gets executed when the plugin processes this data.

Impact: Hackers can execute arbitrary code on your server, potentially taking full control of your website and accessing all data stored within it.

↗ View on NVD
CRITICAL CVE-2020-7947 9.8/10 · CVSS v3.1 ⏱ Immediate
Auth0 Login Plugin - User Data Not Protected

The Login by Auth0 plugin before version 4.0.0 doesn't properly check or clean user data before exporting it. This means attackers can inject malicious code through fields that export user information.

Impact: Sensitive user data could be stolen or exposed. Attackers could also inject code that affects all users accessing your login system or their exported data.

↗ View on NVD

Additional Vulnerabilities (229 more)

Showing first 10 of 229. View all on NVD ↗

CVE IDSeverityScore PublishedDescription
CVE-2022-0836 CRITICAL 9.8 2022-05-09 The SEMA API WordPress plugin before 4.02 does not properly sanitise and escape some parameters before using them in SQL statements via an AJAX action, leading to SQL Injections e…
CVE-2022-4047 CRITICAL 9.8 2022-12-26 The Return Refund and Exchange For WooCommerce WordPress plugin before 4.0.9 does not validate attachment files to be uploaded via an AJAX action available to unauthenticated user…
CVE-2023-3197 CRITICAL 9.8 2023-06-24 The MStore API plugin for WordPress is vulnerable to Unauthenticated Blind SQL Injection via the 'id' parameter in versions up to, and including, 4.0.1 due to insufficient escapin…
CVE-2016-15042 CRITICAL 9.8 2024-10-16 The Frontend File Manager (versions < 4.0), N-Media Post Front-end Form (versions < 1.1) plugins for WordPress are vulnerable to arbitrary file uploads due to missing file type va…
CVE-2025-6441 CRITICAL 9.8 2025-07-24 The Webinar Solution: Create live/evergreen/automated/instant webinars, stream & Zoom Meetings | WebinarIgnition plugin for WordPress is vulnerable to unauthenticated login token …
CVE-2021-24884 CRITICAL 9.6 2021-10-25 The Formidable Form Builder WordPress plugin before 4.09.05 allows to inject certain HTML Tags like <audio>,<video>,<img>,<a> and<button>.This could allow an unauthenticated, remo…
CVE-2020-5391 HIGH 8.8 2020-04-01 Cross-site request forgery (CSRF) vulnerabilities exist in the Auth0 plugin before 4.0.0 for WordPress via the domain field.
CVE-2020-7948 HIGH 8.8 2020-04-01 An issue was discovered in the Login by Auth0 plugin before 4.0.0 for WordPress. A user can perform an insecure direct object reference.
CVE-2020-13641 HIGH 8.8 2020-05-28 An issue was discovered in the Real-Time Find and Replace plugin before 4.0.2 for WordPress. The far_options_page function did not do any nonce verification, allowing for requests…
CVE-2021-24160 HIGH 8.8 2021-04-05 In the Reponsive Menu (free and Pro) WordPress plugins before 4.0.4, subscribers could upload zip archives containing malicious PHP files that would get extracted to the /rmp-menu…
Full Report Available

All 235 CVEs with AI explanations + fix guide

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How to Fix These Vulnerabilities

Conclusion

WordPress 4.0 represents a critical security liability for any active website, with 235 documented vulnerabilities waiting to be exploited by cybercriminals. The 12 critical-level flaws—including Remote Code Execution and SQL injection attacks—pose an immediate threat to your data, customer information, and site reputation. Delaying this upgrade is not an option if you want to protect your business and maintain visitor trust.

Don't let your WordPress site become another breach statistic. Use SiteRecipe.com's vulnerability scanner to identify all security weaknesses on your WordPress installation, receive personalized remediation guidance, and track your security improvements over time. Our platform makes it easy to prioritize fixes, manage updates efficiently, and ensure your website stays protected against emerging threats. Start your free security assessment today and take the first step toward a safer, more secure WordPress experience.

Frequently Asked Questions

Is WordPress 4.0 still safe to use in 2024?
No, WordPress 4.0 is not safe to use in 2024. It stopped receiving security updates years ago, leaving it vulnerable to all newly discovered exploits. With 235 known vulnerabilities including 12 critical flaws, running WordPress 4.0 exposes your site to immediate hacking risks. You should upgrade to the latest WordPress version immediately.
What are the risks of not upgrading from WordPress 4.0?
Not upgrading leaves your site vulnerable to Remote Code Execution attacks, SQL injection, data theft, malware infection, and complete site takeover. Hackers specifically target outdated WordPress versions because they know the vulnerabilities won't be patched. Your visitors' data and your business reputation are at severe risk.
Can I upgrade WordPress 4.0 directly to the latest version?
While you can upgrade directly to the latest version, it's safer to test the upgrade on a staging environment first to ensure plugin and theme compatibility. Major version jumps may require adjustments to custom code or deprecated plugins. Most hosting providers offer one-click upgrades that handle this safely, or you can use trusted plugins like All in One WP Migration to facilitate the transition.
Which plugins are causing critical vulnerabilities in WordPress 4.0?
Several plugins have critical vulnerabilities including Widget Options (Remote Code Execution), Quick Chat (SQL Injection), All-in-One WP Security and Firewall (SQL Injection), Formidable Forms (Unsafe Deserialization), and Login by Auth0 (Input Validation Flaws). You should immediately update or remove any of these plugins if installed, or upgrade WordPress entirely for maximum protection.
How do I know if my WordPress site has been hacked due to these vulnerabilities?
Signs of compromise include unexpected files in your wp-content or wp-admin directories, strange user accounts you didn't create, suspicious database modifications, and malicious code in your theme or plugin files. Use security plugins like Wordfence or Sucuri to scan for infections, and check your server logs for unauthorized access attempts. If you suspect compromise, restore from a clean backup immediately.

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DISCLAIMER: This report is based on publicly available CVE data from the National Vulnerability Database (NVD) maintained by NIST. Detection of a technology version does not confirm active exploitation on any specific website. For informational purposes only. SiteRecipe is not responsible for actions taken based on this report. Always consult a qualified security professional.

Source: nvd.nist.gov · Published: June 07, 2026 · SiteRecipe.com