Overview
A Stored Cross-Site Scripting (XSS) vulnerability has been identified in the YouTube Subscribe WordPress plugin, tracked as CVE-2025-12025. This vulnerability affects versions up to and including 3.0.0. Attackers with administrator-level permissions can inject malicious JavaScript code into the plugin’s settings, which will then execute in the browsers of other users accessing the affected pages. This can lead to account compromise, data theft, or other malicious activities. The vulnerability is only exploitable on multi-site installations or when the unfiltered_html capability has been disabled.
Technical Details
The vulnerability stems from insufficient input sanitization and output escaping within the plugin’s admin settings. Specifically, user-supplied data is not properly validated or encoded before being stored in the database and subsequently rendered in the plugin’s output. The vulnerable code can be found within the sm-youtube-subscription-shortcode.php file.
Examining the relevant code snippets (as referenced in the provided URLs) reveals the areas where the unsanitized input is processed and used in the plugin’s functionality:
- Line 242 (Example – Specific variable not provided but the principle stands)
- Line 246 (Example – Specific variable not provided but the principle stands)
These lines (and similar ones) within the admin settings forms do not properly sanitize input before using it. This allows for injection of Javascript Code.
CVSS Analysis
- CVE ID: CVE-2025-12025
- Severity: MEDIUM
- CVSS Score: 4.4
A CVSS score of 4.4 indicates a Medium severity vulnerability. This takes into account the need for administrative access to exploit the vulnerability. The attack vector is network based, complexity is low, authentication is required, confidentiality impact is low, integrity impact is low, and availability impact is none. The need for admin access lowers the score compared to a publicly facing attack.
Possible Impact
Successful exploitation of this vulnerability could have significant consequences, including:
- Account Takeover: An attacker could potentially inject code to steal administrator session cookies, leading to complete account takeover.
- Malicious Redirection: Injecting malicious JavaScript can redirect users to phishing sites or other harmful websites.
- Defacement: An attacker could modify the appearance of the affected pages to display unwanted or offensive content.
- Data Theft: The attacker could steal sensitive data from the website, such as user credentials or customer information.
Mitigation or Patch Steps
The recommended mitigation steps are:
- Update the Plugin: The best course of action is to update the YouTube Subscribe plugin to the latest version as soon as a patched version is released by the plugin developer. Check the WordPress plugin repository for updates.
- Disable the Plugin: If an update is not immediately available, consider temporarily disabling the plugin until a patched version is released.
- Restrict User Permissions: Limit administrator access to only those users who absolutely need it.
- Input Sanitization and Output Escaping: If you are a developer and maintaining this plugin, ensure that all user inputs are properly sanitized and all outputs are properly escaped to prevent XSS vulnerabilities.
References
- CVE: CVE-2025-12025
- Wordfence Threat Intelligence: Wordfence Analysis
- WordPress Plugin Page: YouTube Subscribe Plugin
- Plugin Source Code: sm-youtube-subscription-shortcode.php (Line 242)
- Plugin Source Code: sm-youtube-subscription-shortcode.php (Line 246)
