CVE-2026-3717 in CV Builder Plugin
Summary
by MITRE • 10/10/2026
The CV Builder – Professional Resume Builder SaaS plugin for WordPress is vulnerable to unauthorized arbitrary file upload due to a missing capability check on the 'wp_save_signature_image' function in all versions up to, and including, 1.3.1. This makes it possible for unauthenticated attackers to upload arbitrary content to the WordPress uploads directory as png files.
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Analysis
by VulDB Data Team • 10/10/2026
The CV Builder – Professional Resume Builder SaaS plugin for WordPress contains a critical security flaw that allows unauthorized users to perform arbitrary file uploads. This vulnerability stems from a missing capability check within the wp_save_signature_image function, which is accessible in all versions of the plugin up to and including version 1.3.1. The absence of proper authorization verification means that any user, even those who are not logged into the WordPress site or lack administrative privileges, can interact with this endpoint directly. This represents a fundamental failure in access control mechanisms, where the application fails to verify whether the requesting entity has the necessary permissions to execute sensitive operations involving file system modifications.
From a technical perspective, the vulnerability exploits the direct exposure of an internal function that handles image processing and storage without validating user roles or capabilities. In standard WordPress development practices, functions that modify server resources must be protected by capability checks such as current_user_can() to ensure only authorized administrators can perform actions like uploading files. By omitting this check, the plugin inadvertently creates a public-facing entry point for file injection. Attackers can craft HTTP requests targeting the wp_save_signature_image endpoint and supply malicious payloads disguised as PNG images. Because WordPress typically stores uploaded files in the uploads directory with predictable paths based on date structures, attackers can predictably place their files within the web-accessible root of the site's media library.
The operational impact of this vulnerability is severe, primarily because it facilitates Remote Code Execution (RCE) when combined with other factors such as server configuration or subsequent exploitation steps. While the immediate result is an arbitrary file upload, the uploaded PNG files are stored in a directory that is often executable by web servers like Apache or Nginx if not properly configured to deny script execution for image directories. An attacker can upload a PHP shell disguised as a PNG file and then execute it via HTTP requests, gaining full control over the underlying server environment. This level of access allows attackers to exfiltrate sensitive data, install additional malware such as webshells or cryptominers, deface the website, or use the compromised server as a pivot point for further attacks against internal networks.
This vulnerability aligns with CWE-434, which describes the unrestricted upload of files with dangerous content, and CWE-285, which covers improper authorization mechanisms. In terms of the MITRE ATT&CK framework, this flaw supports techniques related to Initial Access via Web Applications (T1190) and Execution via Command and Scripting Interpreter through uploaded scripts (T1059). The lack of input validation on file types combined with insufficient access control creates a high-risk scenario that is frequently targeted by automated scanning tools and botnets seeking easy entry points into WordPress ecosystems.
To mitigate this vulnerability, site administrators must immediately update the CV Builder plugin to version 1.3.2 or later, where the capability check has been implemented in the wp_save_signature_image function. Until an official patch is available, it is advisable to disable any functionality related to signature uploads if not strictly necessary for business operations. Additionally, server-level hardening should be reviewed to ensure that the WordPress uploads directory does not allow execution of PHP or other script languages. Configuring web servers like Apache with Options -ExecCGI and using .htaccess rules to deny access to executable file types in upload directories can provide a critical layer of defense against exploitation even if an attacker successfully bypasses application-level controls. Regular security audits and the use of Web Application Firewalls (WAFs) that detect anomalous POST requests to known vulnerable endpoints can also help identify and block attempted exploits before they succeed.