Overview
CVE-2025-13739 identifies a stored Cross-Site Scripting (XSS) vulnerability found in the CryptX plugin for WordPress. Versions of the plugin up to and including 4.0.4 are affected. This vulnerability allows authenticated attackers with contributor-level access or higher to inject malicious JavaScript code into pages via the plugin’s cryptx shortcode. When a user views a page containing the injected script, the script will execute, potentially allowing the attacker to steal sensitive information, redirect users to malicious websites, or perform actions on behalf of the user.
Technical Details
The vulnerability arises due to insufficient input sanitization and output escaping within the cryptx shortcode. Specifically, user-supplied attributes passed to the shortcode are not properly validated or encoded before being rendered in the HTML output. This allows an attacker to inject arbitrary HTML and JavaScript code by crafting a malicious cryptx shortcode within a post or page.
The vulnerable code can be found in the following files within the CryptX plugin up to version 4.0.4:
CVSS Analysis
The Common Vulnerability Scoring System (CVSS) score for CVE-2025-13739 is 6.4, indicating a MEDIUM severity vulnerability. This score is based on the following factors:
- Attack Vector (AV): Network (N)
- Attack Complexity (AC): Low (L)
- Privileges Required (PR): Low (L)
- User Interaction (UI): Required (R)
- Scope (S): Changed (C)
- Confidentiality Impact (CI): Low (L)
- Integrity Impact (II): Low (L)
- Availability Impact (AI): None (N)
The vulnerability requires user interaction because a victim must visit a page containing the injected script. However, the low privileges required (contributor) and low attack complexity make it relatively easy for attackers to exploit.
Possible Impact
A successful exploitation of this vulnerability could lead to:
- Account Compromise: An attacker could steal user cookies and session data, allowing them to hijack user accounts.
- Malicious Redirects: Users could be redirected to phishing sites or other malicious websites.
- Website Defacement: An attacker could modify the content of the affected page or potentially the entire website.
- Malware Distribution: The injected script could be used to distribute malware to unsuspecting users.
Mitigation and Patch Steps
The primary mitigation step is to update the CryptX plugin to the latest version. Check the WordPress plugin repository or the plugin developer’s website for updates. If an update is not yet available, consider temporarily disabling the plugin until a patched version is released.
Additionally, consider the following general security best practices:
- Implement a Web Application Firewall (WAF): A WAF can help detect and block malicious requests, including XSS attacks.
- Regularly Scan Your Website: Use a security scanner to identify potential vulnerabilities.
- Follow the Principle of Least Privilege: Grant users only the minimum level of access required to perform their tasks.
- Educate Users: Train users to recognize and avoid phishing attacks and other social engineering tactics.
