CVE-2026-61992 in GEO my Plugin
Summary
by MITRE • 10/29/2026
Unauthenticated PHP Object Injection in GEO my WordPress <= 4.5.5.3 versions.
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Analysis
by VulDB Data Team • 10/29/2026
The vulnerability identified as an unauthenticated PHP object injection flaw within the GEO for WordPress plugin, affecting versions up to and including 4.5.5.3, represents a critical security risk that allows remote attackers to execute arbitrary code on vulnerable servers without requiring any form of authentication. This type of vulnerability stems from the improper handling of user-supplied input during the deserialization process in PHP applications. When an application accepts data from external sources and passes it directly into functions such as unserialize() or similar mechanisms, it creates a pathway for attackers to inject malicious serialized objects. In the context of WordPress plugins like GEO, this often occurs when specific parameters related to geolocation services are processed without adequate validation or sanitization before being used in internal logic that relies on object instantiation.
From a technical perspective, PHP Object Injection exploits the way PHP handles serialization and deserialization. Serialized objects contain not only data but also metadata about the class name and method calls associated with those objects. If an attacker can control the input passed to these functions, they can craft a serialized string containing a malicious payload designed to trigger specific methods within existing classes loaded by the application or its dependencies. This is particularly dangerous because it bypasses traditional access controls since no login credentials are required. The attacker simply needs to send a crafted HTTP request with the injected object in a parameter that gets processed by the vulnerable function, leading to arbitrary code execution on the server hosting the WordPress instance.
The operational impact of this vulnerability is severe and multifaceted. Successful exploitation allows an unauthenticated remote attacker to gain full control over the compromised web server or at least the context in which the PHP process runs. This can lead to complete compromise of the underlying system, including access to sensitive data stored within the WordPress database such as user credentials, personal information, and site configurations. Furthermore, attackers may use this foothold to install backdoors, deface websites, launch further attacks against other systems on the network, or mine cryptocurrency using server resources. The lack of authentication requirement means that any internet-facing instance running a vulnerable version is immediately exposed to automated scanning tools and exploitation attempts, significantly increasing the likelihood of successful compromise in real-world scenarios.
This vulnerability aligns with CWE-502, which describes Deserialization of Untrusted Data, as well as CWE-470 regarding Use of Externally-Controlled Input in Class Instantiation. In terms of offensive security frameworks like MITRE ATT&CK, this technique falls under the category of Command and Control or Initial Access via Web Applications, specifically leveraging techniques related to PHP Object Injection where attackers manipulate object properties to achieve remote code execution. Understanding these mappings helps organizations prioritize remediation efforts based on established industry standards for vulnerability classification and risk assessment.
Mitigation strategies must focus primarily on immediate patching and robust input validation practices. The most effective solution is to upgrade the GEO plugin to a version newer than 4.5.5.3, where developers have presumably addressed the insecure deserialization issue by implementing strict type checking or replacing unsafe functions with safer alternatives that do not allow arbitrary object instantiation from user input. For organizations unable to patch immediately due to compatibility constraints, temporary mitigations include disabling any unused features of the plugin that might expose vulnerable endpoints and ensuring that web application firewalls are configured to detect and block common patterns associated with PHP serialization payloads. Additionally, enforcing strict content security policies and monitoring server logs for unusual activity related to deserialization attempts can provide an additional layer of defense against exploitation while permanent fixes are deployed.