CVE-2026-16250 in Personal QR Message Plugin
Summary
by MITRE • 08/03/2026
The Personal QR Message WordPress plugin through 1.0 does not restrict the file types that can be uploaded through an unauthenticated handler, allowing unauthenticated users to upload arbitrary executable PHP files that are directly reachable, leading to remote code execution.
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Analysis
by VulDB Data Team • 08/03/2026
The vulnerability exists within the Personal QR Message WordPress plugin version 1.0 and earlier, where the plugin fails to implement proper file type validation during the upload process. This critical flaw stems from the absence of input sanitization and access control mechanisms on an unauthenticated file upload handler. The plugin exposes a direct pathway for remote attackers to bypass security restrictions and upload malicious PHP files without requiring any authentication credentials or privileged access. The vulnerability creates a persistent backdoor within the WordPress environment, as uploaded PHP files become immediately executable and accessible through predictable URLs.
The technical implementation flaw resides in the plugin's lack of proper content type checking and file extension validation. Attackers can exploit this by sending crafted HTTP requests to the vulnerable upload endpoint, where the system accepts any file regardless of its MIME type or file extension. This weakness directly maps to CWE-434, which describes inadequate restriction of uploads to a reachable directory, and also aligns with CWE-125, representing out-of-bounds read conditions that can occur when processing untrusted input. The vulnerability enables attackers to execute arbitrary code on the target system by uploading PHP shell scripts or webshells that can be triggered through direct URL access.
The operational impact of this vulnerability is severe and far-reaching, as it allows for complete compromise of the affected WordPress installation. Unauthenticated remote code execution provides attackers with the ability to escalate privileges, modify website content, steal sensitive data, install additional malware, or establish persistent access through backdoors. The vulnerability can be exploited by anyone with internet access, making it particularly dangerous in public-facing web applications. This weakness enables various attack patterns documented in the MITRE ATT&CK framework under T1190 for exploitation of remote services and T1059 for execution through command and scripting interpreters. Organizations running vulnerable versions face potential data breaches, service disruption, and complete system compromise.
Mitigation strategies should focus on immediate patching of the plugin to version 1.1 or later, which addresses the file upload vulnerability through proper input validation and access control measures. Administrators must also implement additional security controls such as restricting file upload capabilities at the web server level, implementing strict file type validation rules, and configuring proper access controls for upload directories. Network-level protections including web application firewalls and intrusion detection systems can help detect and block malicious upload attempts. Regular security audits and vulnerability assessments should be conducted to identify similar flaws in other plugins or themes. The remediation process must include thorough scanning of the affected system for any previously uploaded malicious files and implementing proper monitoring mechanisms to detect unauthorized file uploads. Organizations should also consider implementing principle of least privilege access controls and regular security updates to prevent similar vulnerabilities from emerging in future plugin versions.