Description

Editor PHP Object Injection in Fluent Boards Pro <= 2.0.11 versions.

Executive Summary

Technical Details

Mitigations

References

Additional Metadata

{
  "score": "7.2",
  "pubDate": "2026-08-27T10:16:37.640Z",
  "pubdate": "2026-08-27T10:16:37.640Z",
  "executiveSummary": "A critical PHP Object Injection vulnerability exists in Fluent Boards Pro, affecting versions 2.0.11 and below.\nThe vulnerability arises from the insecure deserialization of user-supplied input, which can be leveraged by an authenticated attacker to manipulate serialized objects.\nSuccessful exploitation allows for arbitrary PHP object injection, potentially leading to Remote Code Execution (RCE), arbitrary file deletion, or sensitive data exposure depending on the available gadget chains within the application's environment.\nThis vulnerability poses a severe risk to the integrity and availability of the host environment, as it grants attackers the capability to execute code in the context of the web server process.\nExploitation generally requires an authenticated session with sufficient privileges to interact with the vulnerable component, making session hijacking or compromised accounts primary vectors for weaponization.\nUsers are strongly advised to update the plugin immediately to remediate the underlying deserialization flaw.",
  "technicalDetails": "The vulnerability is rooted in the improper handling of serialized data within Fluent Boards Pro. The application accepts user-provided input that is subsequently processed by PHP's unserialize() function without sufficient validation or sanitization.\nPHP Object Injection occurs when an attacker passes a specially crafted serialized string into the application. By supplying a malicious payload containing serialized object structures, an attacker can manipulate the internal state of the application's objects.\nThe attack flow initiates when the attacker identifies an entry point—such as a specific parameter or HTTP request—that passes data into the vulnerable unserialize() routine. The attacker constructs a serialized object that specifies a desired class existing within the application or its dependencies, such as the WordPress core, common plugins, or themes.\nIf the application includes 'magic methods' (such as __destruct, __wakeup, or __toString) within the available classes, these methods are automatically triggered during or after the deserialization process. An attacker can leverage these methods to form a 'POP' (Property Oriented Programming) chain.\nThrough the execution of these gadget chains, the attacker can force the application to execute arbitrary code. This process does not necessarily require the existence of a single vulnerable function, but rather a sequence of object properties that, when deserialized and garbage collected, invoke secondary functions that perform unauthorized actions.\nBecause the payload is executed within the context of the web server, the attacker inherits the system permissions of the service account running the PHP process. This allows for post-exploitation activities such as the installation of web shells, modification of database contents, or lateral movement within the network if the server is improperly segmented.\nThis vulnerability affects versions 2.0.11 and earlier. It requires an authenticated user with appropriate access to the vulnerable interface to trigger the exploit, although the impact is comprehensive due to the potential for full server compromise."
}