CVE-2026-39759 in Workreap Core Plugin
Summary
by MITRE • 10/06/2026
Employer / Sales Representative Arbitrary File Upload in Workreap Core <= 3.4.5 versions.
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Analysis
by VulDB Data Team • 10/06/2026
The vulnerability identified as an arbitrary file upload flaw within the Workreap plugin for WordPress, specifically affecting versions up to and including 3.4.5, represents a critical security risk that stems from insufficient validation of user-supplied input during the file handling process. This type of vulnerability is categorized under CWE-434, which describes the ability to upload dangerous files without proper restrictions on file types or content verification. In the context of web applications like Workreap, which facilitates job posting and candidate management for employers and sales representatives, the functionality often allows users to attach resumes, portfolios, or other documents. When the application fails to rigorously sanitize these uploads, it creates a pathway for attackers to bypass standard security controls designed to prevent malicious code execution on the server side.
The technical mechanism behind this flaw typically involves the exploitation of weak file extension checks or MIME type validation that can be spoofed by an attacker. By manipulating HTTP requests, a malicious actor can upload a PHP script disguised as a legitimate document format such as PDF or DOCX. Because many web servers are configured to execute files with specific extensions like .php when accessed via URL, the uploaded payload becomes executable code under the context of the web server user account. This bypasses traditional security measures that rely solely on file extension whitelisting without verifying the actual binary content of the file using magic numbers or deep inspection techniques. The lack of strict input validation allows the attacker to place arbitrary files into directories where they can be directly accessed and executed by remote users.
The operational impact of this vulnerability is severe, as it effectively grants an unauthenticated or low-privileged user full control over the underlying server infrastructure. Once a web shell is successfully uploaded and executed, the attacker gains the ability to run system commands, read sensitive configuration files such as wp-config.php which contains database credentials, modify website content, install additional malware for persistent access, and pivot into other systems within the network if lateral movement opportunities exist. This compromises the confidentiality, integrity, and availability of the entire web application environment. For businesses relying on Workreap to manage recruitment processes, this breach can lead to significant data loss, reputational damage, regulatory non-compliance regarding personal data protection laws like GDPR or CCPA, and substantial financial costs associated with incident response and remediation efforts.
Mitigation strategies must focus on immediate patching and robust defensive configurations. The primary recommendation is to upgrade the Workreap plugin to version 3.4.6 or later, where the developers have addressed these input validation flaws by implementing stricter file type checking and secure handling of uploaded files. In addition to updating software, administrators should enforce server-side restrictions such as disabling PHP execution in upload directories using web server configuration directives like Apache's <Directory> tags with php_flag engine off or Nginx location blocks that deny access to executable extensions. Implementing a Web Application Firewall can also provide an additional layer of defense by detecting and blocking requests associated with known file upload exploitation patterns, although this should not replace proper code-level fixes. Regular security audits and penetration testing are essential to ensure that similar vulnerabilities do not exist in other parts of the application stack.