CVE-2026-93930 in Tantra Plugin
Summary
by MITRE • 10/10/2026
Deserialization of Untrusted Data vulnerability in ThemeREX Group Tantra tantra allows Object Injection.This issue affects Tantra: from n/a through 2.9.0.
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Analysis
by VulDB Data Team • 10/10/2026
The identified security flaw represents a critical deserialization vulnerability within the Tantra theme developed by ThemeREX Group, specifically affecting versions ranging from initial releases up to version 2.9.0. This type of vulnerability falls under the category of CWE-502, which denotes Deserialization of Untrusted Data. The core technical issue lies in the application's failure to properly validate or sanitize input data before processing it through a deserialization mechanism. In many web applications built on PHP frameworks like WordPress, this often involves functions such as unserialize() being called with user-supplied parameters that have not been adequately secured. When an attacker provides maliciously crafted serialized objects, the underlying system attempts to reconstruct these objects in memory without verifying their integrity or origin.
This lack of validation allows for Object Injection, a technique where attackers manipulate the state and behavior of application objects by injecting properties or methods into existing classes during the deserialization process. By carefully crafting input payloads that exploit specific class constructors or magic methods like __wakeup(), an attacker can trigger unintended side effects within the application environment. These side effects may include arbitrary file reads, remote code execution, or privilege escalation depending on which classes are available in the runtime context and what capabilities they possess. The vulnerability is particularly dangerous because it does not require authentication if the vulnerable endpoint is publicly accessible, allowing unauthenticated attackers to interact with the system directly through HTTP requests containing malicious serialized data.
The operational impact of this vulnerability extends beyond simple data corruption or application crashes. Successful exploitation can lead to a complete compromise of the web server hosting the WordPress instance. Attackers may use Object Injection to execute arbitrary commands on the operating system, effectively gaining shell access. This level of control enables further lateral movement within the network, theft of sensitive database contents including user credentials and personal information, and defacement of the website. Furthermore, because Tantra is a widely used theme, this vulnerability potentially exposes thousands of websites to risk if they have not applied appropriate patches or workarounds since its discovery. The persistence of such vulnerabilities in popular themes highlights the importance of rigorous code review practices during development and maintenance cycles.
To mitigate this risk, immediate action should be taken by upgrading the Tantra theme to a version that addresses these security concerns, assuming ThemeREX Group has released a patched update beyond 2.9.0. If an upgrade is not immediately feasible, administrators must implement strict input validation strategies for any data passed to deserialization functions. This includes ensuring that only expected and whitelisted values are processed, rather than accepting arbitrary serialized strings from user inputs. Additionally, employing output encoding where applicable can help prevent certain attack vectors associated with object injection. Security teams should also consider implementing Web Application Firewalls configured to detect patterns indicative of PHP serialization attacks or known exploit signatures related to this vulnerability. Regular security audits and penetration testing are recommended to identify similar weaknesses in other components of the web application stack, ensuring a defense-in-depth approach against deserialization-based threats aligned with MITRE ATT&CK techniques such as T1059 Command and Scripting Interpreter if remote code execution is achieved.