CVE-2026-93931 in Smash Plugin
Summary
by MITRE • 10/10/2026
Deserialization of Untrusted Data vulnerability in ThemeREX Group Smash smash allows Object Injection.This issue affects Smash: from n/a through 1.12.0.
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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 WordPress plugin developed by ThemeREX Group, specifically known as Smash. This type of vulnerability arises when an application accepts serialized objects from external sources without adequate validation or sanitization before processing them. In this specific instance, the lack of proper input verification allows attackers to inject malicious PHP objects into the system's execution flow. The issue impacts all versions of the plugin ranging from its initial release up through version 1.12.0, indicating a persistent and widespread exposure across multiple deployments that have not yet applied the necessary patches or workarounds.
From a technical perspective, object injection occurs when an attacker crafts a serialized payload containing a malicious class instance with properties designed to exploit existing functionality within the application's codebase. When the vulnerable component deserializes this data, it instantiates these objects and may inadvertently trigger dangerous methods such as file operations, remote code execution calls, or database manipulations depending on which classes are available in the global scope of the WordPress environment. This mechanism bypasses standard authentication checks if the deserialization happens during a request that does not require administrative privileges, thereby allowing unauthenticated attackers to achieve arbitrary code execution with the permissions of the web server process.
The operational impact of this vulnerability is severe and potentially catastrophic for affected websites. Successful exploitation can lead to full remote code execution on the hosting environment, granting attackers complete control over the underlying system. This capability enables a wide range of malicious activities including but not limited to defacement of the website, theft of sensitive user data such as credentials or personal information, installation of backdoors for persistent access, and use of the compromised server as part of a botnet for distributed denial-of-service attacks. Furthermore, because WordPress plugins often interact with databases and other core files, this vulnerability can serve as an initial foothold for deeper lateral movement within the hosting infrastructure, compromising not just the specific site but potentially adjacent sites sharing the same resources.
This flaw aligns closely with Common Weakness Enumeration identifier CWE-502 which describes deserialization of untrusted data. It also maps to MITRE ATT&CK techniques related to command and script interpretation as well as persistence mechanisms that attackers utilize after gaining initial access through such injection flaws. The absence of strict type checking or allow-listing for serialized classes is the root cause, highlighting a failure in implementing secure coding practices regarding external input handling.
To mitigate this risk, immediate action is required by administrators using affected versions of the Smash plugin. The primary remediation step involves updating the plugin to a version released after 1.12.0 where the vulnerability has been addressed through proper validation and sanitization of deserialized inputs. If an update is not immediately available or feasible due to compatibility constraints, temporary mitigations should be implemented at the web server level by restricting file uploads and disabling dangerous PHP functions if possible. Additionally, implementing a Web Application Firewall with rules specifically tuned to detect serialized payload patterns can provide a layer of defense against exploitation attempts while permanent fixes are deployed. Regular security audits and adherence to secure coding standards that prioritize input validation over output encoding will help prevent similar vulnerabilities in future developments.