CVE-2026-28139 in Ajax Search Lite Plugin
Summary
by MITRE • 08/06/2026
Unauthenticated PHP Object Injection in Ajax Search Lite <= 4.14.4 versions.
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Analysis
by VulDB Data Team • 08/06/2026
The vulnerability identified as unauthenticated php object injection in Ajax Search Lite plugin versions up to 4.14.4 represents a critical security flaw that allows attackers to execute arbitrary code on affected systems without requiring authentication credentials. This type of vulnerability falls under the CWE-502 category, specifically classified as "Deserialization of Untrusted Data," which occurs when applications deserialize data from untrusted sources without proper validation or sanitization mechanisms. The attack vector exploits the plugin's handling of user-supplied input through ajax requests, where serialized php objects are processed without adequate security controls.
The technical implementation of this vulnerability stems from the plugin's failure to properly validate and sanitize input parameters before deserializing php objects within its ajax search functionality. Attackers can craft malicious serialized objects that, when processed by the vulnerable plugin, trigger unintended code execution on the target server. This occurs because the application accepts serialized data through GET or POST parameters and directly passes it to php's unserialize function without proper security measures such as input validation, whitelisting, or cryptographic signatures. The flaw exists in the plugin's core processing logic where user-controllable data flows into the deserialization pipeline.
The operational impact of this vulnerability is severe and far-reaching for affected systems. Successful exploitation can lead to complete compromise of wordpress installations running vulnerable versions of the Ajax Search Lite plugin, enabling attackers to execute arbitrary commands, access sensitive data, modify website content, or establish persistent backdoors. The unauthenticated nature of the attack means that any visitor to the affected website can potentially exploit this vulnerability without needing to authenticate, making it particularly dangerous for publicly accessible wordpress installations. This type of vulnerability directly maps to several ATT&CK techniques including T1059.007 for command and script interpreter execution and T1203 for exploitation for privilege escalation.
Mitigation strategies should focus on immediate remediation through plugin updates to versions 4.14.5 or later, which contain fixes for the deserialization vulnerability. System administrators should also implement additional security measures such as input validation at multiple layers, proper parameter sanitization before processing, and network-level protections including web application firewalls that can detect and block malicious serialized object patterns. The fix typically involves implementing strict input validation, using alternative data serialization formats that are less prone to injection attacks, or employing cryptographic signatures to verify the integrity of serialized data before deserialization occurs. Organizations should also conduct thorough security assessments of their wordpress installations to identify other potentially vulnerable plugins and ensure comprehensive patch management processes are in place to prevent similar vulnerabilities from occurring in the future.