CVE-2019-25217 in Speed Optimizer Plugin
Summary
by MITRE • 10/16/2024
The SiteGround Optimizer plugin for WordPress is vulnerable to authorization bypass leading to Remote Code Execution and Local File Inclusion in versions up to, and including, 5.0.12 due to incorrect use of an access control attribute on the switch_php function called via the /switch-php REST API route. This allows 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 • 12/23/2025
The SiteGround Optimizer plugin for WordPress presents a critical security vulnerability identified as CVE-2019-25217, affecting versions up to and including 5.0.12. This vulnerability stems from a fundamental flaw in the plugin's access control implementation, specifically within the switch_php function that is exposed through the /switch-php REST API route. The flaw represents a classic authorization bypass vulnerability that can be exploited to achieve remote code execution and local file inclusion attacks, making it particularly dangerous for WordPress installations that rely on this plugin for performance optimization and site management.
The technical implementation of this vulnerability involves the improper handling of access control attributes within the switch_php function, which is designed to switch PHP versions on the server. When attackers exploit this weakness through the REST API endpoint, they can manipulate the function parameters to include arbitrary files from the server filesystem. This misconfiguration creates a pathway for attackers to execute PHP code contained within these included files, effectively bypassing the intended access controls and permissions. The vulnerability specifically leverages the fact that certain file types, particularly images and other seemingly "safe" file formats, can be uploaded to the server and subsequently included through the vulnerable function, creating a vector for code execution.
The operational impact of this vulnerability extends beyond simple remote code execution to encompass a broader range of malicious activities that can compromise the entire WordPress installation and underlying server infrastructure. Attackers can utilize this vulnerability to bypass existing access controls, potentially gaining unauthorized access to sensitive administrative functions and data. The ability to include and execute arbitrary files opens pathways for data exfiltration, where sensitive information can be extracted from the server, and for persistent access through backdoor installations. Additionally, the vulnerability can be exploited to perform further attacks within the network, as the compromised WordPress installation can serve as a foothold for lateral movement and escalation of privileges.
Security practitioners should implement multiple layers of mitigation to address this vulnerability, beginning with immediate plugin updates to versions that have corrected the access control implementation. The vulnerability aligns with CWE-284, which describes improper access control, and maps to ATT&CK technique T1059.007 for execution through PHP scripts, highlighting the need for comprehensive security measures including web application firewalls, proper file upload restrictions, and network segmentation to limit the potential impact of such exploitation. Organizations should also conduct thorough security assessments of their WordPress installations, review file permissions, and implement monitoring for unusual file inclusion patterns to detect potential exploitation attempts. The vulnerability demonstrates the critical importance of proper access control implementation in REST API endpoints and serves as a reminder of the potential consequences when authentication and authorization mechanisms are improperly configured in web applications.