Description

Unauthenticated PHP Object Injection in Ninja Forms - Layout & Styles <= 3.0.31 versions.

Executive Summary

Technical Details

Mitigations

References

Additional Metadata

{
  "score": "8.8",
  "pubDate": "2026-09-02T12:17:13.287Z",
  "pubdate": "2026-09-02T12:17:13.287Z",
  "executiveSummary": "The Ninja Forms - Layout & Styles plugin for WordPress, specifically versions 3.0.31 and earlier, contains a critical vulnerability categorized as Unauthenticated PHP Object Injection.\nThis security flaw arises due to improper handling of serialized data, which allows an unauthenticated remote attacker to inject malicious PHP objects into the application context.\nBy leveraging this vulnerability, an attacker can trigger insecure deserialization, potentially leading to Remote Code Execution (RCE), arbitrary file deletion, or sensitive data exposure depending on the available PHP gadgets present within the WordPress environment.\nThe vulnerability is particularly severe because it does not require prior authentication or elevated privileges, making it accessible to any external attacker capable of reaching the site's web server.\nSuccessful exploitation poses a critical risk to the confidentiality, integrity, and availability of the target WordPress installation, as it allows for complete server compromise if the site's environment contains exploitable gadget chains.\nUsers are strongly advised to update the plugin to the latest available version to remediate the underlying flaw in the deserialization process.",
  "technicalDetails": "The vulnerability originates from the improper usage of PHP's unserialize() function on user-supplied input within the Ninja Forms - Layout & Styles plugin.\nWhen the plugin processes data related to layout configurations or styles without sufficient validation or sanitization, it inadvertently allows an attacker to control the data stream passed to the deserialization routine.\nIn PHP, the unserialize() function can instantiate arbitrary objects if the application includes a 'POP' (Property Oriented Programming) chain or suitable gadget classes within the codebase or loaded dependencies.\nAn unauthenticated attacker can craft a malicious serialized payload containing a serialized object. When this payload is processed by the vulnerable component, the PHP engine reconstructs the object, triggering the execution of 'magic methods' (such as __wakeup(), __destruct(), or __toString()) defined within the injected class.\nThe attack flow proceeds as follows: 1. The attacker identifies an entry point within the plugin that accepts serialized input. 2. The attacker crafts a malicious payload that specifies a target class available in the site's PHP environment. 3. The attacker injects this payload via a direct HTTP request. 4. The application processes the input and calls unserialize(). 5. The PHP engine instantiates the object, executing the associated magic methods with the attacker-controlled properties. 6. If the chosen gadget chain allows for file operations or command execution, the attacker achieves arbitrary execution in the context of the web server process.\nBecause the vulnerability exists in the plugin's core data handling logic, it is accessible over the network without requiring any session tokens, cookies, or administrative access. This lack of authentication requirements significantly widens the attack surface, allowing automated exploitation attempts to target the site's specific endpoint directly.\nThe post-exploitation impact is extensive. Beyond initial code execution, an attacker may leverage the vulnerability to manipulate application settings, inject malicious administrative users, modify existing content, or deploy web shells to maintain persistent backdoor access to the WordPress environment."
}