Description

Deserialization of Untrusted Data vulnerability in ThemeREX Group Edema edema allows Object Injection.This issue affects Edema: from n/a through 1.2.2.2.

Executive Summary

Technical Details

Mitigations

References

Additional Metadata

{
  "score": "9.8",
  "pubDate": "2026-10-10T08:17:06.557Z",
  "pubdate": "2026-10-10T08:17:06.557Z",
  "executiveSummary": "The ThemeREX Edema WordPress theme, specifically versions 1.2.2.2 and earlier, contains a critical Deserialization of Untrusted Data vulnerability.\nThis flaw enables Object Injection, potentially allowing an unauthenticated or authenticated attacker to execute arbitrary code or manipulate application logic by supplying malicious serialized data.\nThe vulnerability arises from the improper handling of user-supplied input before passing it to PHP's unserialize() function.\nSuccessful exploitation poses a severe risk to the integrity, availability, and confidentiality of the host environment, as it could lead to Remote Code Execution (RCE) or privilege escalation depending on the environment configuration and available PHP gadget chains.\nImpacts include full system compromise, unauthorized data access, and persistent backdoors.\nRemediation requires immediate update to the latest patched version, if available, or removal of the vulnerable theme component.",
  "technicalDetails": "The vulnerability is a classic PHP Object Injection (CWE-502) caused by the insecure use of the unserialize() function on untrusted user-supplied data within the Edema theme codebase.\nIn PHP, the unserialize() function reconstructs stored values from a serialized string. When this function is applied to data controlled by an attacker, the application can be tricked into instantiating arbitrary objects that are present within the application's scope (or via loaded plugins/themes).\nThe attack flow begins when an attacker identifies an endpoint in the Edema theme that accepts serialized input via HTTP parameters or cookies. The attacker crafts a malicious serialized payload designed to leverage 'gadget chains'—a sequence of existing class methods ('magic methods' like __wakeup, __destruct, or __toString) that, when chained together, perform unintended actions.\nWhen the application deserializes the crafted payload, it populates the properties of the injected object. Once the object is destroyed or invoked, the magic methods are triggered automatically by the PHP engine. If a valid gadget chain exists within the theme or the underlying WordPress installation, the attacker can achieve Remote Code Execution (RCE), file system manipulation, or database modification.\nBecause WordPress themes often include various third-party libraries and complex class structures, the potential for discovering a functional gadget chain is significantly elevated. The vulnerability affects the Edema theme from version n/a through 1.2.2.2.\nThis vulnerability is particularly dangerous because it bypasses standard input sanitization, as the object is reconstructed in its entirety. The exploitation typically does not require specific elevated privileges, assuming the vulnerable endpoint is accessible to the public or the target user account, effectively granting the attacker the same permissions as the application's service account.\nThe post-exploitation impact includes the ability to execute arbitrary PHP code on the server, potentially allowing an attacker to install web shells, exfiltrate the WordPress database containing user credentials and site configurations, or pivot into the internal network infrastructure. Furthermore, because this occurs at the application level, standard Web Application Firewalls (WAFs) may fail to detect the payload unless they are specifically configured to inspect and validate serialized structures."
}