CVE-2026-66672 in Flatastic Plugin
Summary
by MITRE • 08/20/2026
Unauthenticated PHP Object Injection in Flatastic <= 2.0 versions.
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Analysis
by VulDB Data Team • 08/20/2026
The vulnerability identified as an unauthenticated PHP object injection flaw within Flatastic versions prior to or equal to 2.0 represents a critical security deficiency that allows attackers to execute arbitrary code on the target server without requiring valid credentials. This type of vulnerability stems from the improper handling of user-supplied input during the deserialization process, where data is converted back into PHP objects in an unsafe manner. In many modern web applications, including those built with frameworks like Laravel which Flatastic utilizes, serialization is often employed to store session data or cache information. When these serialized strings are derived from untrusted sources such as HTTP request parameters, cookies, or headers without adequate validation and sanitization, they become a vector for exploitation. The attacker can craft a maliciously formatted string that, when deserialized by the application, triggers the instantiation of arbitrary classes with controlled properties, leading to remote code execution.
The technical mechanism behind this flaw typically involves the presence of PHP magic methods such as __wakeup(), __destruct(), or __toString() within classes available in the application's environment. These methods are automatically invoked during deserialization and can be leveraged by an attacker if they have knowledge of the class names and their internal structure, often referred to as a gadget chain. By manipulating the serialized payload, the adversary can force the application to execute unintended operations, such as reading sensitive files from the filesystem, executing system commands via functions like exec() or shell_exec(), or interacting with database services in unauthorized ways. Since this vulnerability is unauthenticated, it significantly lowers the barrier for entry, allowing any internet-facing user with basic knowledge of exploitation techniques to compromise the underlying infrastructure. This aligns closely with CWE-502, which describes deserialization of untrusted data as a fundamental weakness that undermines application integrity and confidentiality.
The operational impact of this vulnerability is severe, potentially resulting in full system compromise. An attacker who successfully exploits this flaw can gain control over the web server process, allowing them to pivot into other parts of the network, exfiltrate sensitive customer or administrative data, deface the website, or deploy additional malware such as cryptominers or ransomware. The lack of authentication requirements means that automated scanning tools and botnets frequently target known vulnerable instances of Flatastic, leading to widespread exploitation attempts across the internet. This poses a significant risk not only to the direct owner of the affected instance but also to any downstream services or databases connected to it, as the compromised server can serve as a launchpad for further attacks against internal resources that may be accessible from the web tier.
To mitigate this vulnerability and prevent future occurrences, immediate action is required to update Flatastic to version 2.1 or later, where the deserialization logic has been secured. In addition to patching, organizations should implement strict input validation on all data points before they are passed to any serialization functions. It is also advisable to disable dangerous PHP magic methods if they are not explicitly required for application functionality and to utilize allowlists rather than deny lists when defining which classes can be deserialized. Furthermore, deploying a Web Application Firewall with rules capable of detecting anomalous serialized payloads or known attack signatures associated with PHP object injection can provide an additional layer of defense. Regular security audits and code reviews focusing on data flow analysis are essential to identify similar patterns in custom application logic, ensuring that the principle of least privilege is maintained throughout the system architecture. This approach aligns with ATT&CK technique T1059, specifically sub-techniques related to command and script interpretation, by addressing the root cause rather than just blocking symptoms after an attack has begun.