Stay informed about a significant security vulnerability, CVE-2025-13311, affecting the Just Highlight WordPress plugin. This article provides a comprehensive overview, technical analysis, and mitigation strategies to protect your WordPress site.
Overview
CVE-2025-13311 identifies a Stored Cross-Site Scripting (XSS) vulnerability within the Just Highlight plugin for WordPress. Versions up to and including 1.0.3 are susceptible. An authenticated attacker with administrator-level privileges or higher can inject malicious JavaScript code into the plugin’s settings, which will then be executed whenever another user (including administrators) accesses the plugin’s settings page. This can lead to account takeover, data theft, or other malicious activities.
Technical Details
The vulnerability stems from the lack of proper input sanitization and output escaping within the ‘Highlight Color’ setting. Specifically, when an administrator configures the plugin, the value provided for the highlight color is not properly sanitized before being stored in the database. Subsequently, when the settings page is rendered, this unsanitized value is output without proper escaping, allowing malicious JavaScript code embedded within the ‘Highlight Color’ setting to execute in the context of the user’s browser. This vulnerability is located around line 169 of the `just-highlight.php` file.
CVSS Analysis
- CVSS Score: 4.4 (Medium)
- Vector: AV:N/AC:H/PR:H/UI:R/S:U/C:L/I:L/A:N
- Explanation: This vulnerability has a CVSS score of 4.4, indicating a medium severity. While it requires a high level of privilege (administrator access) and user interaction (accessing the plugin settings page), it allows for the compromise of confidentiality and integrity to a limited extent.
Possible Impact
Successful exploitation of this vulnerability can have severe consequences:
- Account Takeover: An attacker could steal administrator session cookies, granting them complete control over the WordPress site.
- Malware Distribution: The injected script could redirect users to malicious websites or inject malware into the site’s pages.
- Data Theft: Sensitive data, such as user credentials or database information, could be stolen.
- Defacement: The attacker could modify the website’s content and deface it.
Mitigation and Patch Steps
The best course of action is to immediately update the Just Highlight plugin to the latest version. If an update is not yet available, consider temporarily disabling the plugin until a patched version is released. As there are no available versions beyond 1.0.3, consider finding an alternative solution. Contact the plugin developer and encourage a patch. You can also implement a Web Application Firewall (WAF) with rules to detect and block XSS attacks.
