WordPress Plugin Vulnerabilities: How to Check & Prevent (2026)

Most hacked WordPress sites are not compromised through WordPress core. They are compromised through an unpatched WordPress plugin vulnerability. A contact form plugin, a caching plugin or a "free download" premium theme can all become a backdoor. Vulnerability scanners run around the clock, and the time between public disclosure and mass exploitation keeps getting shorter.

In this guide, TeamDevDesign brings together the latest data (covering 2025), walks through five real CVE incidents, explains the risks of nulled themes and plugins, and gives you a practical process to choose secure WordPress plugins, check whether a plugin is vulnerable and update without breaking your site. The final section is for PHP developers who want to write safer plugins.

Note: This is a defensive article. Vulnerabilities are explained at a conceptual level so you can protect your own site. No exploitation steps are provided.

Contents:

• 1. Why WordPress plugin vulnerabilities are the biggest risk
• 2. Five real plugin vulnerabilities (with CVEs)
• 3. Nulled themes and plugins: cheap now, costly later
• 4. How to choose secure WordPress plugins
• 5. How to check if a plugin is vulnerable
• 6. An update strategy that won't break your site
• 7. Handling abandoned or closed plugins
• 8. For developers: writing secure plugins
• 9. Summary checklist
• 10. FAQ
• Conclusion

1. Why WordPress plugin vulnerabilities are the biggest risk

WordPress core is reviewed by a large community and ships automatic security releases. Plugins and themes are different: each is written by a separate developer, and code quality and patch speed vary widely. A typical site runs 15 to 30 plugins, which means 15 to 30 "code suppliers" running with full privileges on your server.

Data from Patchstack's State of WordPress Security in 2026 report (covering 2025) makes this clear:

• In 2025 there were 11,334 new vulnerabilities in the WordPress ecosystem, up 42% from 2024.
• 91% were in plugins and 9% in themes. WordPress core had only 6, all low priority.
• 46% had no developer fix at the time of public disclosure.
• For the most heavily exploited flaws, the weighted median time from disclosure to mass exploitation was about 5 hours.
• Premium is not automatically safer: according to the same report, premium components had three times more known exploited vulnerabilities (KEVs) than free ones.

In other words, keeping core up to date is necessary but not enough. For a broader overview of WordPress weak points (configuration, hosting, accounts), read our guide to common WordPress security vulnerabilities and fixes.

Common types of plugin vulnerabilities

Patchstack reports that Broken Access Control was the most exploited vulnerability type in 2025. It is also the easiest mistake for developers to make, which we cover in section 8.

2. Five real WordPress plugin vulnerabilities (with CVEs)

The incidents below are public, have CVE IDs, and their version data is verified on NVD, Wordfence or Patchstack. All have been patched. The point is that even popular, well-maintained plugins can have bugs, and your update speed is what matters most.

WP File Manager – CVE-2020-25213

According to NVD, File Manager (wp-file-manager) before 6.9 shipped an elFinder example connector file that could be accessed directly, allowing unauthenticated users to upload PHP code. It was exploited in the wild in August and September 2020, when the plugin had roughly 700,000 active installs, and it is listed in CISA's Known Exploited Vulnerabilities catalog. Lesson: plugins that manipulate files should be updated first, and removed when not in use.

LiteSpeed Cache – CVE-2024-28000

According to Wordfence and NVD, the plugin's role simulation feature relied on a weak hash, letting unauthenticated visitors impersonate an administrator. It was reported through Patchstack's Zero Day program, scored CVSS 9.8, and affected a plugin with more than 5 million installs. Version 6.4 (released August 13, 2024) fixed it. Lesson: performance plugins can carry critical bugs too, not just security or form plugins.

Really Simple Security – CVE-2024-10924

According to Wordfence, versions 9.0.0 to 9.1.1.1 (Free, Pro and Pro Multisite) mishandled errors in the two-factor REST API, allowing login to any account when 2FA was enabled. The plugin had more than 4 million installs and the flaw scored CVSS 9.8. The developer worked with WordPress.org to force-update sites to 9.1.2. Lesson: security plugins need regular updates too, and you should verify the installed version yourself rather than relying only on auto-updates.

OttoKit (SureTriggers) – CVE-2025-3102

According to NVD, versions up to 1.0.78 lacked an empty-value check on the secret key, allowing admin account creation when the plugin was active but not configured with an API key. Version 1.0.79 fixed it. Patchstack observed automated attacks only hours after disclosure. Lesson: a plugin installed and left unconfigured is still attack surface.

Post SMTP – CVE-2025-24000

According to the Patchstack database, versions up to 3.2.0 only checked that a user was logged in, not their capabilities, so low-privileged accounts such as Subscribers could read email logs, including password reset emails. Version 3.3.0 (June 2025) added a manage_options check. Lesson: if your site allows user registration, missing capability checks are more dangerous than they look.

3. Nulled themes and plugins: cheap now, costly later

A nulled theme or plugin is a cracked premium product with its license checks removed, distributed for free on sharing sites. Small site owners often use them to save money, but they are one of the most common infection sources.

• Bundled malware: According to Wordfence, nulled plugins and themes frequently contain backdoors, inject hidden admin users into the database, and are used for SEO spam or visitor redirects. Wordfence's report on 2020 found about 206,000 sites infected with malware from nulled plugins or themes, more than 17% of the infected sites it detected.
• No security updates: Nulled copies don't update through official channels. When a CVE like the ones above is published, sites running nulled copies stay stuck on the vulnerable version.
• Hard to detect: The malware is often obfuscated and may stay dormant for weeks. The site looks fine while Google has already started showing warnings.
• Copyright issues: Premium products are licensed under the developer's terms. Using a cracked copy can infringe copyright and the terms of use, and you lose access to support.

If your site runs a nulled product, deleting it is not enough. Assume the site may already be compromised: scan for malware, look for unknown admin accounts, and change passwords and secret keys. The full process is in our guide on what to do when your WordPress site is hacked.

4. How to choose secure WordPress plugins

No plugin is free of bugs, but choosing carefully reduces risk significantly. Before clicking "Install", check the following:

1. Source: only download from the WordPress.org plugin directory or the developer's official site. Never install .zip files from sharing sites, social groups or shortened links.
2. Last updated: prefer plugins updated within the past 6 months. WordPress.org shows a warning when a plugin hasn't been tested with the latest 3 major WordPress releases, which is a red flag.
3. Compatibility: check "Tested up to" and the required PHP version against what your server runs.
4. Vulnerability history: search the plugin on WPScan, Wordfence Intelligence or the Patchstack Database. Past vulnerabilities are not a deal-breaker; what matters is how quickly they were fixed.
5. Support: look at the Support tab, the share of resolved threads in the last two months and how the developer responds.
6. Security policy: serious developers usually publish a vulnerability disclosure page or join a bug bounty program.
7. Installs and ratings: a large install base doesn't guarantee safety, but a larger community tends to find and report bugs sooner.
8. Keep it minimal: if a feature takes a few lines in a child theme or an existing plugin, don't add a new one. Every plugin removed is less attack surface.

5. How to check if a plugin is vulnerable

You don't need to read source code to know whether your site runs a known WordPress plugin vulnerability. The tools below compare your plugins and versions against vulnerability databases.

A 15-minute weekly routine

1. Open Site Health and resolve update-related recommendations.
2. On the Plugins screen, filter by "Update Available" and read the changelogs for words like "security" or "vulnerability". Security releases go first.
3. Review the Wordfence or Patchstack report and note any plugin with an unpatched vulnerability.
4. If you manage the site over SSH, WP-CLI gives a quick list:

# Plugins with an update available
wp plugin list --update=available --fields=name,version,update_version

# Inactive plugins (candidates for removal)
wp plugin list --status=inactive --fields=name,version

Important: a deactivated plugin that hasn't been deleted is still on the server. With flaws like the WP File Manager one, the vulnerable file can still be reached directly even when the plugin is inactive. If you don't use it, delete it.

6. An update strategy that won't break your site

Many people avoid updates after one bad "white screen" experience. The answer isn't to stop updating; it's to update with a process.

Step 1: Always back up before updating

Back up both files and the database, store them away from the web server, and test restores regularly. If you run a VPS, see our guide to securing a Linux VPS for beginners to set up backups and a firewall at the server level.

Step 2: Test on staging for important sites

Online stores and heavily customized sites should have a staging copy. Update staging first, test key flows such as cart, contact forms and login, then update production.

Step 3: Use selective auto-updates

Since WordPress 5.5 you can enable auto-updates per plugin and theme. A sensible approach:

• Enable auto-updates for small plugins that rarely affect the front end and have a stable release history (SMTP, security, sitemap plugins).
• Update manually with testing for large plugins such as page builders, WooCommerce and its extensions, and multilingual plugins.
• Update the same day when a changelog or security alert mentions a serious vulnerability. When exploitation happens within hours, waiting until month-end is too late.

Step 4: Add protection while waiting for a patch

Since nearly half of vulnerabilities have no fix at disclosure, a web application firewall (WAF) or virtual patching service can block known exploits until the developer ships a fix. This is an extra layer, not a replacement for updating.

If you don't have time for weekly checks, TeamDevDesign's website maintenance and management service can handle backups, updates and vulnerability monitoring on a regular schedule.

7. Handling abandoned or closed plugins

An abandoned plugin is one that hasn't been updated for a long time. A closed plugin has been removed from WordPress.org, and its page shows "This plugin has been closed". Reasons include guideline violations, author request or an unresolved security issue.

The danger is that WordPress doesn't remove closed plugins from your site, and no updates will arrive. Here's how to handle them:

1. Inventory: list your plugins with each one's last update date. Security plugins such as Wordfence or Patchstack can alert you when a plugin is closed or abandoned.
2. Assess: does the plugin handle user data, file uploads, login or REST API endpoints? If so, replacing it is high priority.
3. Find a replacement: choose a maintained plugin using the criteria in section 4, or rewrite small features in your own code.
4. Migrate on staging: move data and settings, test thoroughly, then apply to production.
5. Delete the old plugin: deactivate and delete it, then confirm nothing is left in wp-content/plugins.

8. For developers: writing secure plugins

If you write plugins or customize themes, most WordPress plugin vulnerabilities can be avoided with four rules: verify nonces, check capabilities, sanitize input, escape output. The official guidance lives in the Security section of WordPress Developer Resources.

Unsafe example

// DON'T: no nonce, no capability check, raw SQL concatenation
add_action( 'wp_ajax_tdd_delete_note', function () {
    global $wpdb;
    $id = $_POST['id'];
    $wpdb->query( "DELETE FROM {$wpdb->prefix}tdd_notes WHERE id = $id" );
    echo 'Deleted ' . $_POST['title'];
    wp_die();
} );

This code has at least four problems: any logged-in account (even a Subscriber) can call it; there's no CSRF protection; input goes straight into SQL; and user data is printed without escaping.

Safer example

add_action( 'wp_ajax_tdd_delete_note', function () {
    // 1. CSRF protection: verify the nonce
    check_ajax_referer( 'tdd_delete_note', 'nonce' );

    // 2. Capability check: a nonce is NOT authorization
    if ( ! current_user_can( 'manage_options' ) ) {
        wp_send_json_error( 'Insufficient permissions', 403 );
    }

    // 3. Sanitize input
    $id    = absint( $_POST['id'] ?? 0 );
    $title = sanitize_text_field( wp_unslash( $_POST['title'] ?? '' ) );

    // 4. Use a prepared statement
    global $wpdb;
    $wpdb->query( $wpdb->prepare(
        "DELETE FROM {$wpdb->prefix}tdd_notes WHERE id = %d",
        $id
    ) );

    // 5. Escape on output
    wp_send_json_success( 'Deleted ' . esc_html( $title ) );
} );

On the form side, generate the nonce with wp_create_nonce( 'tdd_delete_note' ) or wp_nonce_field(). According to the Nonces documentation, a nonce is valid for about 12 to 24 hours by default and should never be relied on for authentication or authorization; that is the job of current_user_can().

REST API: don't use __return_true for sensitive routes

register_rest_route( 'tdd/v1', '/logs', array(
    'methods'             => 'GET',
    'callback'            => 'tdd_get_logs',
    // Check a specific capability, not just "logged in"
    'permission_callback' => function () {
        return current_user_can( 'manage_options' );
    },
) );

The Post SMTP issue in section 2 is exactly this mistake: checking "logged in" instead of a specific capability.

Quick reference: sanitizing and escaping

Also validate uploaded files with wp_check_filetype_and_ext() instead of trusting the extension sent by the user. General PHP principles such as preventing SQL injection, XSS and unsafe uploads are covered in more depth in our article on PHP security vulnerabilities and prevention.

9. Summary checklist to prevent WordPress plugin vulnerabilities

• ☐ Install plugins and themes only from WordPress.org or official developers; never use nulled copies.
• ☐ Delete unused plugins and themes, don't just deactivate them.
• ☐ Enable vulnerability alerts (Wordfence, Patchstack or WPScan).
• ☐ Check Site Health and pending updates every week.
• ☐ Apply critical security updates the same day.
• ☐ Automate off-server backups and test restores regularly.
• ☐ Use staging for important sites.
• ☐ Enable selective auto-updates for small, stable plugins.
• ☐ Replace abandoned or closed plugins.
• ☐ Protect the login page with 2FA and login rate limiting (see our WordPress login security guide).
• ☐ Developers: nonce + current_user_can() + sanitize/escape + $wpdb->prepare().

10. FAQ

Conclusion

WordPress plugin vulnerabilities can't be eliminated entirely, because all software has bugs. But a few simple habits reduce the risk a great deal: choose plugins carefully, avoid nulled copies, monitor vulnerability alerts, update with a process and delete what you don't use. For developers, nonces, capability checks, sanitizing and escaping are the foundation of every secure plugin.

If you need help auditing plugins and setting up alerts and an update process for your WordPress site, contact TeamDevDesign for advice tailored to your site.