CVE-2026-1426
Published: 18 February 2026
Summary
CVE-2026-1426 is a high-severity Deserialization of Untrusted Data (CWE-502) vulnerability in Wordpress (inferred from references). Its CVSS base score is 8.8 (High).
Operationally, exploitation aligns with the MITRE ATT&CK technique Exploit Public-Facing Application (T1190); ranked at the 36.4th percentile by exploit likelihood (below the median); it is not currently listed in the CISA KEV catalog.
The strongest mitigations our analysis identified are NIST 800-53 SI-10 (Information Input Validation) and SI-2 (Flaw Remediation).
Deeper analysis
CVE-2026-1426 is a PHP Object Injection vulnerability (CWE-502) affecting the Advanced AJAX Product Filters plugin for WordPress in all versions up to and including 3.1.9.6. The issue arises from deserialization of untrusted input in the shortcode_check function within the plugin's Live Composer compatibility layer. Exploitation requires the Live Composer plugin to be installed and active on the target WordPress site. The vulnerability has a CVSS v3.1 base score of 8.8 (AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H).
Authenticated attackers with Author-level access or higher can exploit this vulnerability over the network to inject a PHP Object. By default, there is no known Property-Oriented Programming (POP) chain in the vulnerable plugin, limiting impact unless another plugin or theme providing a POP chain is installed. In such cases, attackers could potentially delete arbitrary files, retrieve sensitive data, or execute arbitrary code, depending on the specific POP chain available.
References include the CWE-502 definition and links to the vulnerable code in the plugin's Live Composer compatibility file at lines 25, 28, and 33, as well as changeset 3449344, which appears to address the issue in the affected file.
OWASP Top 10 for Web (2025)
EU & UK References
- 🇪🇺 ENISA EUVD: EUVD-2026-8088
Vulnerability details
The Advanced AJAX Product Filters plugin for WordPress is vulnerable to PHP Object Injection in all versions up to, and including, 3.1.9.6 via deserialization of untrusted input in the shortcode_check function within the Live Composer compatibility layer. This makes it…
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possible for authenticated attackers, with Author-level access and above, to inject a PHP Object. No known POP chain is present in the vulnerable software, which means this vulnerability has no impact unless another plugin or theme containing a POP chain is installed on the site. If a POP chain is present via an additional plugin or theme installed on the target system, it may allow the attacker to perform actions like delete arbitrary files, retrieve sensitive data, or execute code depending on the POP chain present. Note: This vulnerability requires the Live Composer plugin to also be installed and active.
- CWE(s)
Related Threats
MITRE ATT&CK Enterprise TechniquesAI
Why these techniques?
PHP object injection in a WordPress plugin directly enables remote exploitation of a public-facing web application (T1190) by authenticated users, with potential for arbitrary code execution when a POP chain is present.
CVEs Like This One
Affected Assets
Mitigating Controls
Mitigating Controls (NIST 800-53 r5) AI
Directly requires identification, reporting, and correction of the PHP object injection flaw via patching the vulnerable Advanced AJAX Product Filters plugin.
Prevents object injection by enforcing validation of untrusted inputs prior to deserialization in the shortcode_check function.
Mitigates risk by prohibiting unapproved user-installed plugins like Advanced AJAX Product Filters and Live Composer unless explicitly authorized.