CVE-2026-112111 in Bootstrap Shortcodes Plugin
Summary
by MITRE • 10/19/2026
The Bootstrap Shortcodes plugin for WordPress before 3.4.6 is vulnerable to stored XSS via the id attribute of the [bs_tcontent] shortcode. The bs_tcontent() shortcode handler in inc/bs_tabs.php emits the id attribute value into an unquoted HTML attribute. esc_attr() is applied, but it does not encode space characters, so a space in the supplied value terminates the attribute and any following text is parsed as additional HTML attributes, including JavaScript event handlers. This allows authenticated attackers with Contributor-level access and above to inject arbitrary web script that executes in the browser of any user who views the page and interacts with the injected element.
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Analysis
by VulDB Data Team • 10/19/2026
The Bootstrap Shortcodes plugin for WordPress versions prior to 3.4.6 contains a critical stored cross-site scripting vulnerability located within the bs_tcontent shortcode handler found in the inc/bs_tabs.php file. This flaw arises from improper input validation and output encoding mechanisms when processing user-supplied data for the id attribute of shortcodes. Specifically, while the application attempts to sanitize inputs using the esc_attr function, this function fails to encode space characters effectively within HTML attributes. Consequently, if an attacker includes a space character in their input, it terminates the intended attribute value prematurely. This allows any subsequent text provided by the attacker to be interpreted as additional HTML attributes rather than part of the original string.
This technical flaw enables authenticated attackers with Contributor-level access or higher to inject arbitrary web scripts into pages managed through this plugin. The vulnerability is classified under CWE-79, which covers Improper Neutralization of Input During Web Page Generation commonly known as Cross-site Scripting. By exploiting the unquoted attribute context and the specific behavior of esc_attr regarding spaces, an attacker can craft a payload that includes JavaScript event handlers such onmouseover or onclick. When these malicious shortcodes are saved to the database, they become persistent within the site content, qualifying this as a stored XSS attack vector rather than a reflected one.
The operational impact of this vulnerability is significant because it allows for the execution of arbitrary client-side code in the context of any user who views the affected page and interacts with the injected element. This interaction can lead to session hijacking, where an attacker steals authentication cookies or tokens associated with active sessions. It also facilitates credential theft through fake login forms embedded within the malicious script, defacement of website content by altering DOM elements, and potentially redirecting users to phishing sites designed to harvest sensitive information further compromising user privacy and data integrity across the WordPress installation.
From a threat intelligence perspective, this vulnerability aligns with MITRE ATT&CK technique T1059 which covers Command Line Interface or Scripting Interpreter execution via browser-based vectors such as JavaScript. The persistence of the payload in stored content means that even if the initial attacker is removed from the system, the malicious code remains active until manually cleaned by an administrator. This creates a long-term risk for organizations relying on this plugin to manage their web presence without immediate patching or mitigation strategies in place.
To mitigate this vulnerability, administrators should immediately upgrade the Bootstrap Shortcodes plugin to version 3.4.6 or later where the encoding logic has been corrected to properly handle space characters and other special symbols within HTML attributes. Until an update is applied, site owners can implement a Web Application Firewall rule that blocks requests containing specific patterns indicative of this exploit such as spaces followed by common JavaScript event handler names inside shortcode parameters. Additionally enforcing strict role-based access control ensures that only trusted administrators with the highest level of privilege can create or edit content using shortcodes reducing the attack surface for lower-privileged users like contributors who might otherwise attempt to inject malicious scripts into published pages.