CVE-2023-6133 in Forminator Plugin
Summary
by MITRE • 11/15/2023
The Forminator plugin for WordPress is vulnerable to arbitrary file uploads due to insufficient blacklisting on the 'forminator_allowed_mime_types' function in versions up to, and including, 1.27.0. This makes it possible for authenticated attackers with administrator-level capabilities or above to upload arbitrary files on the affected site's server, but due to the htaccess configuration, remote code cannot be executed.
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Analysis
by VulDB Data Team • 04/11/2026
The vulnerability identified as CVE-2023-6133 resides within the Forminator plugin for WordPress, a widely used form building solution that has been found to contain a critical security flaw in its file upload validation mechanisms. This issue affects versions up to and including 1.27.0, representing a significant risk to WordPress installations that rely on this plugin for form management and user interaction. The vulnerability stems from inadequate input validation and sanitization within the plugin's core functionality, specifically within the 'forminator_allowed_mime_types' function that controls which file types can be uploaded through the plugin's forms. The flaw allows for bypassing the intended security restrictions that should prevent malicious file uploads, creating a pathway for potential attackers to compromise the affected WordPress environment.
The technical nature of this vulnerability places it squarely within the realm of CWE-434, which encompasses insecure file upload mechanisms that allow attackers to upload malicious files to a server. The weakness manifests when authenticated attackers with administrator-level privileges or higher exploit the insufficient blacklisting mechanism to upload arbitrary file types. While the vulnerability does not directly enable remote code execution due to the presence of htaccess restrictions, it creates a dangerous scenario where attackers can upload potentially harmful files such as web shells, malicious scripts, or other exploit payloads that could be leveraged for further compromise. The attack vector requires authentication and administrative privileges, which limits its exposure but does not eliminate the risk, particularly in environments where administrative credentials might be compromised or where privilege escalation occurs through other means.
The operational impact of CVE-2023-6133 extends beyond immediate file upload capabilities, as it represents a potential gateway for more sophisticated attacks within the WordPress ecosystem. Even without direct remote code execution, the ability to upload malicious files provides attackers with opportunities to establish persistence, conduct data exfiltration, or deploy additional malware within the compromised environment. The vulnerability's exploitation requires an attacker to already possess administrative access, which suggests that the attack surface is limited to scenarios where administrative credentials have been compromised through phishing, credential stuffing, or other social engineering techniques. However, the risk remains significant because administrators often have broad system access and can potentially leverage this vulnerability to escalate their privileges further or gain access to sensitive data stored within the WordPress installation.
Organizations affected by CVE-2023-6133 should immediately implement the vendor-provided patch or upgrade to a version that resolves the file upload validation issue. The recommended mitigation strategy includes updating to the latest version of the Forminator plugin where the vulnerability has been addressed through enhanced MIME type validation and improved blacklisting mechanisms. System administrators should also consider implementing additional security measures such as monitoring file upload activities, implementing stricter file type restrictions at the web server level, and conducting regular security audits of WordPress plugins and themes. Network segmentation and access control measures can help limit the potential impact of a successful exploitation attempt, while regular security assessments can identify other vulnerabilities that might be exploited in conjunction with this flaw. The vulnerability also highlights the importance of maintaining current security practices and ensuring that all WordPress components are regularly updated to protect against known security issues.