CVE-2026-93934 in Partiso Plugin
Summary
by MITRE • 10/10/2026
Deserialization of Untrusted Data vulnerability in ThemeREX Group Partiso partiso allows Object Injection.This issue affects Partiso: from n/a through 1.1.13.
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Analysis
by VulDB Data Team • 10/10/2026
The identified security flaw represents a critical deserialization of untrusted data vulnerability within the Partiso theme developed by ThemeREX Group, specifically affecting versions ranging from initial releases up to version 1.1.13. This category of vulnerability is fundamentally rooted in the application's failure to properly validate or sanitize input before processing it through a serialization mechanism that can reconstruct complex object structures. In many modern web applications and content management systems, particularly those built on PHP frameworks like WordPress which ThemeREX products typically utilize, data deserialization allows for the conversion of serialized objects back into their native state within memory. When an application accepts user-supplied input and directly passes it to a deserialization function without adequate safeguards, it creates a pathway for attackers to inject malicious object graphs that can alter program flow or execute arbitrary code during the reconstruction process.
The technical mechanism behind this vulnerability involves the exploitation of PHP's unserialize function or similar serialization handlers found in other languages such as Java or Python. An attacker crafts a specially formatted serialized payload containing an instance of a class with magic methods, such as __wakeup(), __destruct(), or __toString(). These methods are automatically invoked when the object is being deserialized or destroyed. By injecting these objects into areas where user input is processed without strict type checking or allow-listing of expected classes, the attacker gains control over which internal functions are executed. This leads to Object Injection, a specific manifestation of insecure deserialization where the injected object allows for unintended side effects within the application's environment. The vulnerability exists because the software does not distinguish between trusted system-generated serialized data and untrusted user-provided input, thereby trusting malicious payloads as legitimate configuration or state data.
From an operational perspective, the impact of this vulnerability is severe and potentially catastrophic depending on the hosting environment and server permissions. Successful exploitation allows a remote attacker to achieve Remote Code Execution (RCE) with the privileges of the web application process. This means that if the web server runs under a user account with limited rights, the attacker may still gain significant control over the file system, database access, or ability to pivot into other internal network segments. In many WordPress environments, this can lead to full site compromise, including defacement, data exfiltration of sensitive customer information stored in the database, and the installation of persistent backdoors such as web shells for ongoing unauthorized access. The attacker does not necessarily need high-level administrative credentials if they can exploit this flaw through lower-privileged roles or public-facing endpoints that accept user input processed by vulnerable theme functions.
This vulnerability aligns with CWE-502, which describes Deserialization of Untrusted Data, and is closely associated with the attack technique known as Insecure Deserialization within the MITRE ATT&CK framework under the Tactic Execution phase. Specifically, it maps to techniques that involve manipulating object properties or invoking magic methods to achieve code execution. The lack of input validation allows for a straightforward exploitation path where no complex bypasses are required beyond crafting the correct serialized payload. Security researchers and penetration testers often look for these patterns in themes and plugins that handle file uploads, form submissions, or API endpoints without implementing strict serialization policies such as whitelisting allowed classes or using secure alternatives like JSON instead of native object serialization when possible.
To mitigate this vulnerability, immediate action is required to update the Partiso theme to a version later than 1.1.13 where the issue has been resolved by ThemeREX Group. The patch likely involves implementing strict input validation, restricting deserialization to only known safe classes via an allow-list mechanism, or replacing unsafe serialization functions with safer data interchange formats like JSON that do not support arbitrary object instantiation. For organizations unable to update immediately due to compatibility constraints, temporary mitigations include disabling file uploads if they are processed through the vulnerable function, implementing Web Application Firewall rules to detect and block common serialized payload patterns such as O: for PHP objects in POST parameters or cookies, and ensuring that error reporting is disabled on production servers to prevent information leakage during exploitation attempts. Regular security audits of third-party themes and plugins are essential to identify similar deserialization flaws before they can be exploited by malicious actors targeting the broader ecosystem of WordPress-based websites.