CVE-2026-39755 in WP Duplicate Plugin
Summary
by MITRE • 10/06/2026
Subscriber Arbitrary File Upload in WP Duplicate <= 1.1.11 versions.
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Analysis
by VulDB Data Team • 10/06/2026
The vulnerability identified as an arbitrary file upload flaw within the WordPress plugin WP Duplicate, specifically affecting versions up to and including 1.1.11, represents a critical security risk that compromises the integrity of web applications relying on this software for content duplication tasks. This type of vulnerability falls under the category of CWE-434, which describes an unrestricted upload of file with dangerous type, allowing attackers to execute arbitrary code on the target server if they can successfully upload and subsequently access malicious files such as PHP scripts or other executable payloads. The root cause typically lies in insufficient validation mechanisms during the file upload process, where the application fails to adequately verify the MIME type, extension, or content of uploaded files against a strict allowlist, thereby permitting attackers to bypass security controls by disguising malicious code within seemingly benign image or document formats.
From an operational perspective, this flaw enables unauthenticated remote attackers to gain unauthorized access to the server environment hosting the vulnerable WordPress instance. By exploiting this weakness, an attacker can upload a web shell, which serves as a backdoor allowing for persistent control over the compromised system. Once the malicious file is uploaded and accessed via its direct URL path, it facilitates further exploitation steps including data exfiltration, installation of additional malware such as ransomware or cryptominers, defacement of the website, and pivoting to other systems within the internal network if lateral movement opportunities exist. This aligns with MITRE ATT&CK technique T1505.003, known as Web Shell, which is commonly used by adversaries to maintain access after initial compromise. The impact extends beyond immediate system takeover, potentially leading to significant reputational damage, loss of customer trust, and regulatory penalties due to the exposure of sensitive user data stored within the WordPress database or associated file systems.
Mitigation strategies for this vulnerability require both immediate remediation and long-term security hardening practices. Administrators must immediately update WP Duplicate to version 1.1.12 or later, where the developers have presumably implemented stricter input validation and sanitization routines to prevent arbitrary uploads. In cases where updating is not feasible due to compatibility constraints, temporary workarounds include disabling file upload functionality within the plugin settings if it is not actively used, restricting write permissions on the WordPress uploads directory so that executable scripts cannot be created or executed there, and implementing a Web Application Firewall (WAF) with rules specifically designed to detect and block attempts to upload PHP files or other dangerous extensions. Additionally, organizations should enforce principle of least privilege by ensuring that web server processes run under restricted user accounts with minimal file system access rights, thereby limiting the potential damage even if an upload succeeds. Regular security audits and penetration testing are recommended to identify similar weaknesses in custom code or third-party plugins before they can be exploited in production environments.