CVE-2026-119526 in Royal Event Plugin
Summary
by MITRE • 10/30/2026
Deserialization of Untrusted Data vulnerability in ThemeREX Royal Event allows Object Injection.
This issue affects Royal Event: from n/a through 2.0.
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Analysis
by VulDB Data Team • 10/30/2026
The identified security flaw represents a critical deserialization vulnerability within the ThemeREX Royal Event plugin, specifically affecting versions ranging from non-existent initial releases up to version 2.0. This type of vulnerability arises when an application accepts untrusted data and passes it directly to a function capable of reconstructing native objects in memory without performing adequate validation or sanitization checks. In the context of PHP-based WordPress plugins like Royal Event, this typically occurs during the processing of serialized arrays passed via HTTP requests, such as POST parameters or cookie values. When the application deserializes these inputs using functions like unserialize() without verifying their integrity or origin, it creates a pathway for attackers to inject malicious object graphs into the system's runtime environment.
The technical mechanism behind this flaw relies on PHP’s ability to automatically invoke magic methods during the unserialization process. If an attacker can control the serialized data structure, they can instantiate arbitrary classes that are available within the application or its dependencies. By carefully crafting a payload, an adversary can manipulate object properties and trigger specific method calls, such as __wakeup(), __destruct(), or other initialization routines. This capability effectively allows for Object Injection, where the attacker gains control over the execution flow of the program by leveraging existing classes to perform unintended actions. The severity is compounded if these available classes interact with sensitive system resources, file systems, or database connections in ways that were not anticipated by the developers.
From an operational perspective, this vulnerability poses a severe risk to the confidentiality, integrity, and availability of the affected web application. Successful exploitation can lead to Remote Code Execution (RCE), allowing attackers to execute arbitrary commands on the server hosting the WordPress instance. This could result in complete compromise of the underlying operating system, theft of sensitive data including user credentials and database contents, or the installation of persistent backdoors for future access. Additionally, attackers might use this vector to deface websites, launch distributed denial-of-service attacks using the compromised server as a botnet node, or pivot into other parts of the internal network if the web server is not properly isolated. The impact extends beyond technical metrics to include significant reputational damage and potential regulatory non-compliance due to data breaches.
This vulnerability aligns with Common Weakness Enumeration (CWE) ID 502, which describes Deserialization of Untrusted Data. It also maps closely to MITRE ATT&CK technique T1059, specifically Command and Scripting Interpreter sub-techniques, as the ultimate goal is often to execute system commands through the injected objects. Furthermore, it relates to CWE 470 regarding Use of Externally-Controlled Input in Deserialization, highlighting the failure to validate input before processing. The lack of strict type checking or allow-lists for expected classes during deserialization is a fundamental design flaw that violates secure coding principles recommended by OWASP and other industry standards.
Mitigation strategies must focus on immediate remediation and long-term defensive posture improvements. For administrators using Royal Event versions up to 2.0, the most effective solution is to upgrade immediately to a patched version where this vulnerability has been addressed by ThemeREX. If upgrading is not feasible in the short term, implementing strict input validation at the entry points of the application can help block malicious payloads before they reach the deserialization logic. Additionally, deploying Web Application Firewalls (WAFs) with rules specifically tuned to detect serialized payload patterns and known exploit signatures for PHP object injection can provide a layer of defense-in-depth. It is also crucial to disable dangerous functions in php.ini if possible and ensure that error reporting does not leak sensitive stack traces to end-users during exploitation attempts, thereby reducing the information available to attackers for refining their payloads.