Urgent: Stored XSS Vulnerability Discovered in Bulma Shortcodes WordPress Plugin (CVE-2025-11802)

Overview

A critical security vulnerability, identified as CVE-2025-11802, has been discovered in the Bulma Shortcodes plugin for WordPress. This flaw exposes websites using the plugin to Stored Cross-Site Scripting (XSS) attacks. All versions of the plugin up to and including version 1.0 are affected.

The vulnerability allows authenticated attackers with contributor-level access or higher to inject malicious JavaScript code into website pages. This code will then execute whenever a user visits the compromised page, potentially leading to account takeover, data theft, or other malicious activities.

Technical Details

The vulnerability lies within the bulma-notification shortcode, specifically in the handling of the type attribute. The plugin fails to properly sanitize user-supplied input to the type attribute and does not adequately escape the output. This lack of input sanitization and output escaping allows attackers to inject arbitrary HTML and JavaScript code into the page.

The vulnerable code resides in the inc/components.php file within the plugin. Specifically, the code responsible for processing the `type` attribute within the notification shortcode is susceptible to injection.

CVSS Analysis

The Common Vulnerability Scoring System (CVSS) score for CVE-2025-11802 is 6.4 (Medium). The CVSS vector string is likely something similar to AV:N/AC:L/PR:L/UI:R/S:C/C:L/I:L/A:N, indicating:

• Attack Vector (AV): Network – The attack can be launched remotely.
• Attack Complexity (AC): Low – The attack requires minimal effort.
• Privileges Required (PR): Low – The attacker needs low-level privileges (e.g., Contributor).
• User Interaction (UI): Required – The attack requires a user to interact with the injected content (e.g., viewing the page).
• Scope (S): Changed – The vulnerability can affect components beyond the vulnerable component itself.
• Confidentiality Impact (C): Low – There is limited confidentiality impact.
• Integrity Impact (I): Low – There is limited integrity impact.
• Availability Impact (A): None – There is no impact on system availability.

Possible Impact

The exploitation of this Stored XSS vulnerability can have significant consequences:

• Account Takeover: An attacker could potentially steal administrator cookies or credentials, gaining full control of the WordPress site.
• Malicious Redirects: Injected scripts could redirect users to phishing websites or other malicious destinations.
• Defacement: Attackers could modify the content of affected pages, defacing the website.
• Data Theft: Sensitive information displayed on the page could be stolen by the injected scripts.
• Malware Distribution: The injected scripts could be used to distribute malware to website visitors.

Mitigation and Patch Steps

The best course of action is to take the following steps:

1. Update the Plugin (If Available): Check for an updated version of the Bulma Shortcodes plugin. If a patch is available, immediately update to the latest version.
2. Disable the Plugin: If an update isn’t available, immediately disable the Bulma Shortcodes plugin to prevent exploitation.
3. Remove the Plugin: If the plugin is no longer required for your site, consider uninstalling it.
4. Review User Roles and Permissions: Ensure that users have the minimum necessary permissions to perform their tasks. Restrict contributor-level access where possible.
5. Web Application Firewall (WAF): Implement a WAF with XSS protection rules to help mitigate the risk of exploitation.
6. Sanitize User Input: If you continue using the plugin and no patch is available, manually sanitize any user-provided input that is used in the type attribute of the bulma-notification shortcode. This is a temporary measure and should not be considered a permanent solution.

References

• Vulnerable Code Location (plugins.trac.wordpress.org)
• Wordfence Threat Intelligence Report (wordfence.com)