CVE-2026-87791 in Design Scuole Italia Plugin
Summary
by MITRE • 09/15/2026
A path traversal vulnerability exists in the reserved_file_check function of the functions.php file in the WordPress Design Scuole Italia theme. The vulnerability allows an unauthenticated attacker to download arbitrary files accessible by the web server process.
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Analysis
by VulDB Data Team • 09/15/2026
The identified security flaw resides within the functions.php file of the WordPress Design Scuole Italia theme, specifically affecting the reserved_file_check function. This component is responsible for validating and handling requests related to specific resources or configurations managed by the theme. The core technical deficiency lies in insufficient input validation regarding user-supplied data passed to this function. Specifically, the implementation fails to adequately sanitize file paths before processing them, allowing an attacker to manipulate path parameters using directory traversal sequences such as dot-dot-slash (../). By injecting these sequences into request arguments, an unauthenticated actor can bypass intended access controls and navigate outside of the designated theme directories or application root. This lack of strict boundary enforcement enables the retrieval of files that are otherwise restricted from public view, provided they fall within the read permissions granted to the web server process on the underlying operating system.
From a technical perspective, this vulnerability is classified under CWE-22: Improper Limitation of a Pathname to a Restricted Directory. The flaw represents a classic example of insecure direct object reference or path traversal where the application trusts user input without verifying that the resolved file path remains within an expected safe directory structure. In many web server configurations, particularly those running on Linux-based systems with standard Apache or Nginx setups, the web process often has read access to configuration files, environment variables, and potentially sensitive source code from other applications hosted on the same server if proper isolation is not enforced. Consequently, this vulnerability can lead to significant information disclosure. An attacker could extract local file contents such as wp-config.php which contains database credentials, .htaccess files that may reveal internal routing logic or security headers, or even system configuration files depending on the specific deployment environment and privilege levels of the web service account.
The operational impact of this vulnerability is severe due to its unauthenticated nature. Since no valid user session or authentication token is required to exploit the flaw, any individual with network access to the vulnerable WordPress instance can attempt exploitation automatically using standard scanning tools or manual requests. The ability to download arbitrary files compromises the confidentiality integrity pillar of information security for the targeted environment. If sensitive configuration data containing database passwords or API keys are exposed, it may facilitate further attacks such as SQL injection via direct database connection attempts, remote code execution through compromised include mechanisms if PHP settings allow local file inclusion, or privilege escalation within the server infrastructure. Furthermore, exposure of internal application logic can aid attackers in crafting more sophisticated payloads against other components of the web stack.
To mitigate this vulnerability, immediate remediation actions should focus on hardening the input validation logic within the reserved_file_check function. Developers must implement strict allowlisting for permitted file extensions and directories rather than relying solely on blacklist approaches which are prone to bypass techniques like double encoding or null byte injection depending on server configuration. It is critical to resolve any symbolic links or relative path components before accessing files, ensuring that the final canonical path remains within a predefined safe base directory using functions such as realpath in PHP combined with strict string comparison against an allowed root path. Additionally, applying principle of least privilege to the web server user account can limit the blast radius by restricting read access only to necessary theme assets and preventing exposure of sensitive system files or configuration data located outside the web root. Regular security audits and static code analysis should be integrated into the development lifecycle to detect similar patterns in future updates. From a defensive posture perspective, this vulnerability aligns with ATT&CK technique T1083: File and Directory Discovery, as it enables an adversary to enumerate and access local files on the compromised system for reconnaissance purposes leading potentially to credential theft or further lateral movement within the network infrastructure hosting the WordPress application.