Overview
A high-severity vulnerability, identified as CVE-2025-12138, has been discovered in the URL Image Importer plugin for WordPress. This vulnerability allows authenticated attackers with Author-level access or higher to upload arbitrary files to the affected server, potentially leading to remote code execution (RCE).
This article provides a detailed analysis of the vulnerability, its potential impact, and recommended mitigation steps.
Technical Details
The vulnerability stems from insufficient file type validation within the uimptr_import_image_from_url() function of the URL Image Importer plugin. Specifically, versions up to and including 1.0.6 rely on the user-controlled Content-Type HTTP header to determine the file type during the upload process. Critically, the plugin writes the file to the server before conducting more robust validation checks. This creates a window of opportunity for an attacker to bypass the initial Content-Type check by sending a malicious file with a misleading Content-Type header (e.g., image/jpeg) but containing PHP code.
Attackers can exploit this by uploading a PHP file disguised as an image. Once uploaded, the attacker can then access the file directly via the webserver, executing the malicious PHP code and potentially gaining control of the server.
The relevant code locations within the plugin are:
uimptr_import_image_from_url()function: plugins.trac.wordpress.org/browser/url-image-importer/trunk/url-image-importer.php#L1319- File writing process: plugins.trac.wordpress.org/browser/url-image-importer/trunk/url-image-importer.php#L1353
- Initial content-type check: plugins.trac.wordpress.org/browser/url-image-importer/trunk/url-image-importer.php#L1358
- File path handling: plugins.trac.wordpress.org/browser/url-image-importer/trunk/url-image-importer.php#L198
CVSS Analysis
The Common Vulnerability Scoring System (CVSS) score for CVE-2025-12138 is 8.8, indicating a HIGH severity. This score reflects the following factors:
- Attack Vector (AV): Network (N)
- Attack Complexity (AC): Low (L)
- Privileges Required (PR): High (H) (Author-level access and above is required)
- User Interaction (UI): None (N)
- Scope (S): Changed (C)
- Confidentiality Impact (C): High (H)
- Integrity Impact (I): High (H)
- Availability Impact (A): High (H)
The high score is primarily driven by the potential for remote code execution, leading to a complete compromise of the affected system.
Possible Impact
Successful exploitation of CVE-2025-12138 can have severe consequences, including:
- Remote Code Execution (RCE): An attacker can execute arbitrary code on the server, potentially gaining full control.
- Website Defacement: Attackers can modify website content, redirect users to malicious sites, or inject malicious code into the website.
- Data Theft: Sensitive data, including user credentials, customer information, and proprietary data, can be stolen.
- Server Compromise: The entire server can be compromised, leading to further attacks on other systems within the network.
Mitigation and Patch Steps
The most effective mitigation is to update the URL Image Importer plugin to the latest version as soon as possible. Check the WordPress plugin repository for updates.
If an update is not yet available, consider temporarily disabling the plugin until a patched version is released. This will prevent potential attackers from exploiting the vulnerability.
As a general security practice, always ensure that all WordPress plugins and themes are up-to-date, and remove any unused or outdated plugins.
References
- URL Image Importer Plugin Code on WordPress Trac: plugins.trac.wordpress.org
- Specific Code Changeset: plugins.trac.wordpress.org/changeset
- Wordfence Threat Intelligence Report: wordfence.com
