Description

The Contact Form, Survey, Quiz & Popup Form Builder – ARForms plugin for WordPress is vulnerable to PHP Object Injection in all versions up to, and including, 1.8.5 via deserialization of untrusted input from form submissions. This makes it possible for unauthenticated attackers to inject a PHP Object. No known POP chain is present in the vulnerable software, which means this vulnerability has no impact unless another plugin or theme containing a POP chain is installed on the site. If a POP chain is present via an additional plugin or theme installed on the target system, it may allow the attacker to perform actions like delete arbitrary files, retrieve sensitive data, or execute code depending on the POP chain present.

Executive Summary

Technical Details

Mitigations

References

Additional Metadata

{
  "score": "9.8",
  "pubDate": "2026-08-16T09:16:19.900Z",
  "pubdate": "2026-08-16T09:16:19.900Z",
  "executiveSummary": "The Contact Form, Survey, Quiz & Popup Form Builder – ARForms plugin for WordPress is vulnerable to PHP Object Injection, specifically stemming from the insecure deserialization of untrusted input handled during form submissions. This security flaw impacts all versions up to, and including, 1.8.5. Unauthenticated remote threat actors can leverage this vector to inject arbitrary PHP objects into the application scope. Although the ARForms plugin itself lacks a native Property-Oriented Programming (POP) chain, the vulnerability becomes critically exploitable if the target WordPress installation contains a separate theme or plugin that harbors a viable POP chain. Depending on the capabilities of the available POP chain, successful exploitation can lead to severe security compromises, including the deletion of arbitrary files, unauthorized retrieval of sensitive data, or Remote Code Execution (RCE) on the underlying server. The absence of authentication requirements significantly lowers the barrier to entry for attackers targeting exposed endpoints.",
  "technicalDetails": "The root cause of this vulnerability lies in the unsafe processing and deserialization of untrusted user input originating from form submissions within the ARForms plugin. When the application passes user-supplied data into PHP's native unserialize() function (or an insecure equivalent) without adequate sanitization or validation, attackers can manipulate the serialized data stream. This allows them to instantiate arbitrary PHP classes present in the application's execution context. Because the vulnerability is exposed via form submission handlers, it is accessible over the network without requiring authentication or specific privileges, granting unauthenticated external entities the ability to interact with the vulnerable component across all affected versions up to and including 1.8.5.\nThe attack flow proceeds as follows: First, an unauthenticated attacker crafts a malicious serialized payload containing object structures designed to interact with classes loaded in the WordPress environment. Second, the attacker transmits this payload via form submission parameters processed by the ARForms plugin. Third, the vulnerable component ingests the input and invokes deserialization on the untrusted data. Fourth, if a compatible POP chain exists within another installed plugin or theme, the PHP runtime automatically invokes magic methods—such as __wakeup() or __destruct()—defined within the gadget classes. Finally, the execution of these magic methods triggers secondary function calls that align with the attacker's objectives, resulting in post-exploitation impacts such as arbitrary file deletion, sensitive data disclosure, or code execution, contingent entirely upon the specific gadget chain present in the target environment."
}