Summary
CVE-2026-28139 is an unauthenticated PHP Object Injection (deserialization of untrusted data) vulnerability in the Ajax Search Lite WordPress plugin by wpdreams. It affects all versions up to and including 4.14.4 and carries a CVSS v3.1 base score of 9.8 (Critical).
Technical details
- Root cause: The plugin deserializes untrusted, attacker-controlled data (CWE-502), allowing PHP object injection (CAPEC-586).
- Trigger conditions: Exploitable by a remote, unauthenticated attacker without user interaction or special privileges.
- Attack vector: Network (AV:N), low attack complexity (AC:L), no privileges required (PR:N).
- Impact: High impact to confidentiality, integrity, and availability. When a suitable PHP gadget chain is present, object injection can lead to actions such as arbitrary code execution, data disclosure, or manipulation on the affected host.
Affected software
- Ajax Search Lite (WordPress plugin, vendor wpdreams): all versions <= 4.14.4.
Severity
- CVSS v3.1 base score: 9.8 (Critical)
- Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
Mitigation and recommended actions
- Immediate: Update Ajax Search Lite to version 4.14.5 or later.
- If no patch can be applied: Deactivate and remove the plugin until it can be updated, and restrict access to the affected WordPress site with a web application firewall or upstream network controls that filter malicious serialized payloads.
How IONIX identifies potentially affected assets
IONIX matches the following signals against data already collected when it crawled the asset; identifying the technology sends no request beyond that crawl.
- Raw response body:
/wp-content/plugins/ajax-search-lite/

