CVE-2026-78566 in Shuffle Plugin
Summary
by MITRE • 08/25/2026
The Shuffle theme for WordPress is vulnerable to Local File Inclusion in all versions up to, and including, 1.8. This makes it possible for unauthenticated attackers to include and execute arbitrary files on the server, allowing the execution of any PHP code in those files. This can be used to bypass access controls, obtain sensitive data, or achieve code execution in cases where images and other “safe” file types can be uploaded and included.
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Analysis
by VulDB Data Team • 08/25/2026
The Shuffle theme for WordPress contains a critical Local File Inclusion vulnerability affecting all versions up to and including 1.8. This security flaw stems from insufficient input validation when handling user-supplied parameters that are subsequently passed to PHP include or require functions without proper sanitization. The absence of strict allowlisting mechanisms allows an attacker to manipulate these inputs, thereby directing the application to load arbitrary files located on the server's file system rather than intended theme assets or configuration files. This type of vulnerability is categorized under CWE-98 Improper Control of Filename for Include/Require Statements in the PHP Application, reflecting a fundamental failure to restrict file access based on user input.
The operational impact of this vulnerability is severe because it permits unauthenticated attackers to execute arbitrary code within the context of the web server process. By including maliciously crafted files that contain PHP payloads, an attacker can achieve remote code execution with the privileges assigned to the web service account. This capability effectively bypasses standard access controls since no authentication credentials are required to exploit the flaw. In scenarios where the WordPress installation allows users to upload images or other file types that might be stored in accessible directories, attackers can leverage these uploads as vectors for inclusion, further expanding the attack surface and facilitating data exfiltration of sensitive information such as database configuration files containing credentials.
From a threat intelligence perspective, this vulnerability aligns with ATT&CK technique T1505.003 Server Side Request Forgery via Web Components or similar server-side code execution patterns where local file inclusion is used to pivot into deeper system compromise. The ability to include arbitrary PHP files means that attackers can potentially read sensitive configuration files like wp-config.php, leading to full database access and complete site takeover. Furthermore, if the web server permits script execution in uploaded directories, the attacker may achieve persistent backdoor installation by uploading a malicious file and then triggering its inclusion through the vulnerable parameter.
Mitigation strategies must prioritize immediate patching of the Shuffle theme to version 1.9 or later where this issue has been resolved. Until an update is applied, administrators should implement strict input validation on all parameters passed to include statements, ensuring that only expected values are processed. Additionally, disabling file inclusion functions for dynamic paths in php.ini can provide a layer of defense-in-depth by preventing the execution of arbitrary files regardless of application logic flaws. Web Application Firewalls may also be configured to detect and block requests containing common local file inclusion patterns such as ../ sequences or attempts to access sensitive system files like /etc/passwd, although reliance on WAFs should not replace direct code remediation.