An important security vulnerability has been discovered affecting the Tab Ultimate plugin for WordPress. The plugin, which is designed to provide flexible and customizable tabs for your website, has been found to be susceptible to Stored Cross-Site Scripting (XSS). This vulnerability impacts all versions up to and including version 1.3 of the plugin. Insufficient input sanitization and output escaping on user-supplied attributes are the underlying causes of this issue.

Product: Tab Ultimate plugin (for WordPress)
Vulnerable versions: Up to and including 1.3
CVE Identifier: CVE-2023-5667
Issue Type: Stored Cross-Site Scripting (XSS)


Stored Cross-Site Scripting (XSS) vulnerabilities occur when an attacker can inject and store malicious scripts on target web pages. These malicious scripts can then be executed whenever a user visits an affected page.

In the case of the Tab Ultimate plugin, the vulnerability is specifically related to the plugin's shortcodes. Authenticated attackers with contributor-level permissions and above can exploit this by injecting arbitrary web scripts that execute upon user interaction. This can then lead to undesired actions such as stealing login credentials, redirecting users to malicious websites, and more.

Exploit Details

The malicious script can be injected through the plugin's shortcodes during the creation or modification of a page or a post using the Tab Ultimate plugin. Here is an example of a malicious shortcode:

[ultimate_tab title="XSS" onclick="alert('XSS Attack!');" ...]

In this example, the attacker has injected a script that displays an alert with the message "XSS Attack!" when clicking on the tab named "XSS". This example is relatively harmless, but much more severe actions could be taken by altering the malicious script.


Since this vulnerability affects all versions of the Tab Ultimate plugin up to and including version 1.3, it is crucial to take action immediately to mitigate the risks. The plugin author has not provided an immediate fix or security patch for this issue; therefore, long-term resolutions are necessary.

1. Disable the plugin: This is the most immediate and effective solution. If there are alternative plugins that provide similar functionality without the security risk, consider switching to them while waiting for the issue to be resolved.
2. Limit contributor access: To minimize the risk that an attacker with contributor-level permissions can exploit this vulnerability, restrict access to trusted individuals.
3. Input/output sanitization: Implement input sanitization and output escaping techniques to reduce the risk of this vulnerability. The WordPress Codex recommends using esc_html() and esc_attr() functions for output escaping and wp_kses() for input sanitization.


1. OWASP Cross-Site Scripting (XSS):
2. Tab Ultimate - WordPress plugin:
3. WordPress Codex - Data Validation:


The Tab Ultimate plugin for WordPress has a critical Stored Cross-Site Scripting (XSS) vulnerability impacting all versions up to and including 1.3. This vulnerability is due to insufficient input sanitization and output escaping on user-supplied attributes. To protect your website, follow the mitigation strategies provided above. As always, exercise caution when using third-party plugins and perform regular security audits to ensure that your website remains safe and secure in the face of potential vulnerabilities.


Published on: 11/22/2023 16:15:00 UTC
Last modified on: 11/28/2023 19:22:00 UTC