CVE-2026-1426 – The Advanced AJAX Product Filters WordPress plu... (How to Fix)

Q: What is the severity of CVE-2026-1426?

CVE-2026-1426 has a CVSS score of 8.8 (HIGH). The Advanced AJAX Product Filters WordPress plugin is vulnerable to PHP object injection via deserialization of untrusted input in the Live Composer compatibility layer. This allows authenticated attackers with Author-level access or higher to inject PHP objects, but exploitation requires both the Live Composer plugin to be active and another plugin/theme containing a POP chain to be installed. Without a POP chain present, the vulnerability has no direct impact.

📋 TL;DR

The Advanced AJAX Product Filters WordPress plugin is vulnerable to PHP object injection via deserialization of untrusted input in the Live Composer compatibility layer. This allows authenticated attackers with Author-level access or higher to inject PHP objects, but exploitation requires both the Live Composer plugin to be active and another plugin/theme containing a POP chain to be installed. Without a POP chain present, the vulnerability has no direct impact.

💻 Affected Systems

Products:

Advanced AJAX Product Filters for WordPress

Versions: All versions up to and including 3.1.9.6

Operating Systems: All operating systems running WordPress

Default Config Vulnerable: ✅ No

Notes: Requires Live Composer plugin to be installed and active; requires Author-level authenticated access; requires another plugin/theme with POP chain for full exploitation

⚠️ Manual Verification Required

This CVE does not have specific version information in our database, so automatic vulnerability detection cannot determine if your system is affected.

Why? The CVE database entry doesn't specify which versions are vulnerable (no version ranges provided by the vendor/NVD).

🔒 Custom verification scripts are available for registered users. Sign up free to download automated test scripts.

Recommended Actions:

Review the CVE details at NVD
Check vendor security advisories for your specific version
Test if the vulnerability is exploitable in your environment
Consider updating to the latest version as a precaution

⚠️ Risk & Real-World Impact

🔴

Worst Case

If a POP chain is present via another plugin/theme, attackers could delete arbitrary files, retrieve sensitive data, or execute arbitrary code on the server.

🟠

Likely Case

Limited impact due to requirement for both Live Composer plugin and specific POP chain in another component; most sites will not have exploitable conditions.

🟢

If Mitigated

No impact if proper access controls prevent Author-level account compromise and no POP chain components are installed.

🌐 Internet-Facing: MEDIUM

🏢 Internal Only: LOW

🎯 Exploit Status

Public PoC: ✅ No

Weaponized: NO

Unauthenticated Exploit: ✅ No

Complexity: HIGH

Exploitation requires multiple conditions: Author-level access, Live Composer plugin active, and presence of POP chain in another component

🛠️ Fix & Mitigation

✅ Official Fix

Patch Version: Versions after 3.1.9.6

Vendor Advisory: https://plugins.trac.wordpress.org/changeset/3449344/

Restart Required: No

Instructions:

1. Update Advanced AJAX Product Filters plugin to latest version via WordPress admin panel. 2. Verify version is greater than 3.1.9.6. 3. No server restart required.

🔧 Temporary Workarounds

Disable Live Composer Compatibility

all

Remove or disable the Live Composer compatibility layer if not using Live Composer plugin

Remove file: wp-content/plugins/woocommerce-ajax-filters/includes/compatibility/live_composer.php

Restrict Author Access

all

Implement strict access controls and monitoring for Author-level accounts

🧯 If You Can't Patch

Remove the Advanced AJAX Product Filters plugin entirely if not essential
Implement web application firewall rules to block suspicious deserialization attempts

🔍 How to Verify

Check if Vulnerable:

Check WordPress admin panel > Plugins > Advanced AJAX Product Filters version. If version is 3.1.9.6 or lower, you are vulnerable.

Check Version:

wp plugin list --name='Advanced AJAX Product Filters' --field=version

Verify Fix Applied:

Verify plugin version is greater than 3.1.9.6 in WordPress admin panel.

📡 Detection & Monitoring

Log Indicators:

Unusual POST requests to WordPress admin-ajax.php with serialized data
Author-level accounts performing unexpected plugin actions
Errors related to deserialization in PHP error logs

Network Indicators:

HTTP requests containing serialized PHP objects in parameters
Unusual traffic patterns from Author-level user accounts

SIEM Query:

source="wordpress.log" AND ("unserialize" OR "live_composer" OR "shortcode_check")

📊 Metadata

CVE ID: CVE-2026-1426

CVSS v3 Score: 8.8 (HIGH)

CVSS Vector: CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H

CWE: CWE-502

Published: February 18, 2026

Last Updated: February 18, 2026

🔗 References

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