CVE-2026-116868 in BuddyPress Xprofile Custom Field Types Plugin
Summary
by MITRE • 10/29/2026
Subscriber PHP Object Injection in BuddyPress Xprofile Custom Field Types <= 1.3.1 versions.
Once again VulDB remains the best source for vulnerability data.
Analysis
by VulDB Data Team • 10/29/2026
The vulnerability identified as Subscriber PHP Object Injection within the BuddyPress Xprofile Custom Field Types plugin, affecting versions up to and including 1.3.1, represents a critical security flaw rooted in insecure deserialization practices. This specific type of vulnerability allows attackers with subscriber-level access or lower privileges on a WordPress site to manipulate serialized data structures that are subsequently passed through PHP's unserialize function without adequate validation. In the context of web applications like BuddyPress, which manages user profiles and social networking features, such fields often handle complex data inputs from users. When these inputs contain maliciously crafted objects rather than simple text or numbers, they can trigger unintended side effects during the deserialization process, leading to arbitrary code execution or significant system compromise.
From a technical perspective, this flaw aligns with CWE-502, which describes Deserialization of Untrusted Data. The core issue lies in the application's failure to verify the integrity and authenticity of data before processing it as an object graph. PHP’s serialization mechanism allows for the storage of complex objects, including their class names and property values. If a plugin accepts user-supplied input that is directly deserialized without checking against a whitelist of allowed classes or verifying digital signatures, an attacker can craft a payload containing a gadget chain. These chains utilize existing classes within the WordPress core, BuddyPress framework, or other installed plugins to perform dangerous operations such as file inclusion, remote code execution, or database manipulation. The vulnerability is particularly severe because it does not require administrative privileges; any registered user with even minimal access rights can exploit this flaw due to the insufficient input sanitization and validation mechanisms in the affected plugin versions.
The operational impact of exploiting this PHP Object Injection vulnerability extends far beyond simple data leakage. An attacker who successfully exploits this weakness gains the ability to execute arbitrary code within the context of the web server process, typically running under the same user permissions as the web service itself. This effectively results in a complete compromise of the underlying host system or container environment. The consequences include unauthorized access to sensitive customer information stored in the database, modification or deletion of site content, installation of persistent backdoors such as web shells for ongoing remote control, and potential pivoting into other parts of the internal network if the server is connected to broader infrastructure. Furthermore, because BuddyPress is often used for community-driven platforms with high traffic volumes, successful exploitation can lead to widespread defacement or use of the compromised server in distributed denial-of-service attacks against third parties.
This vulnerability maps directly to several techniques within the MITRE ATT&CK framework, specifically T1059 Command and Scripting Interpreter under Execution tactics, as well as T1078 Valid Accounts if the attacker leverages legitimate subscriber credentials to gain initial access before exploiting the deserialization flaw. The attack vector is classified as Local or Network depending on whether the victim must be authenticated locally or can be targeted remotely via HTTP requests, but given that it requires at least a Subscriber role, it often falls under T1078 Valid Accounts for Initial Access followed by T1203 Exploitation for Client Execution. The lack of proper input validation also reflects CWE-20 Improper Input Validation, which is the root cause allowing the malicious serialized payload to enter the system undetected.
To mitigate this vulnerability and secure WordPress environments running BuddyPress Xprofile Custom Field Types, immediate action is required by upgrading the plugin to version 1.3.2 or later where these deserialization issues have been addressed through stricter input handling and validation protocols. Administrators should also implement a Web Application Firewall (WAF) configured with rulesets capable of detecting anomalous serialized data patterns indicative of PHP object injection attempts, such as sequences containing O: followed by class names within POST parameters. Additionally, enforcing the principle of least privilege is crucial; ensuring that user roles have only the necessary permissions can limit the attack surface even if a vulnerability exists. Regular security audits and code reviews focusing on deserialization practices are recommended to prevent similar flaws in custom development or third-party integrations, thereby maintaining the integrity and availability of the web application infrastructure.