CVE-2026-109147 in WP Booking System Plugin
Summary
by MITRE • 10/22/2026
The WP Booking System WordPress plugin before 2.1.0.3 does not validate and escape one of its parameters before reflecting it back in an admin page, leading to Reflected Cross-Site Scripting which could be used against high privilege users such as administrators.
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Analysis
by VulDB Data Team • 10/22/2026
The vulnerability identified in the WP Booking System WordPress plugin prior to version 2.1.0.3 represents a classic instance of reflected cross-site scripting resulting from insufficient input validation and output escaping mechanisms within an administrative interface. This security flaw stems directly from CWE-79, which categorizes improper neutralization of input during web page generation as a critical weakness in web application architecture. The core technical issue lies in the plugin's failure to properly sanitize user-supplied data before it is immediately reflected back into the HTML response served by an admin page. When an administrator interacts with specific features of the booking system, such parameters are processed without adequate filtering or encoding, allowing malicious scripts embedded within those inputs to execute directly in the context of the victim browser session.
From a technical perspective, this vulnerability exploits the trust relationship between the WordPress administration dashboard and its users. Because the affected code path is located on an admin page rather than a public-facing endpoint, the exploitation requires that the target user possess administrative privileges or at least elevated capabilities within the WordPress environment. An attacker can craft a malicious URL containing script payloads in one of these vulnerable parameters and trick an administrator into clicking it via phishing techniques or other social engineering methods. Upon execution, the injected JavaScript runs with the same permissions as the admin account, effectively bypassing standard browser security models like the Same-Origin Policy because the code originates from the trusted domain itself.
The operational impact of this vulnerability is severe due to the high privilege level associated with WordPress administrators. Successful exploitation allows an attacker to perform a wide range of malicious actions that compromise the integrity and confidentiality of the entire website ecosystem. These actions include stealing session cookies or authentication tokens, which can lead to complete account takeover if combined with other techniques like cross-site request forgery. Furthermore, attackers can manipulate the DOM to deface the administrative interface, redirect users to phishing sites designed to harvest credentials, or exfiltrate sensitive data stored within the WordPress database through JavaScript-based keyloggers or form grabbers. The ability to execute arbitrary code in an admin context effectively grants full control over the web application and potentially the underlying server if further exploitation chains are developed.
This vulnerability aligns with several tactics defined in the MITRE ATT&CK framework, particularly those related to initial access and credential harvesting. It falls under techniques such as Valid Accounts for Initial Access when combined with phishing, or Collection via Browser Data Extraction during post-exploitation phases where session cookies are targeted. The lack of proper output encoding also relates to CWE-80, which covers improper neutralization of script-related HTML tags in a web page, highlighting the fundamental failure in secure coding practices within the plugin's development lifecycle.
To mitigate this vulnerability and prevent similar issues in future updates, developers must implement strict input validation and robust output escaping for all data reflected back into HTML contexts. This involves using WordPress-specific functions like esc_html or wp_kses_post to ensure that any user-supplied content is treated as plain text rather than executable code when rendered in the browser. Additionally, implementing Content Security Policy headers can provide an additional layer of defense by restricting the sources from which scripts are allowed to execute. For site administrators currently running versions prior to 2.1.0.3, immediate action should be taken to upgrade the plugin to the patched version or disable it entirely until a fix is available. Regular security audits and adherence to secure coding standards such as those outlined in OWASP guidelines are essential for maintaining the resilience of WordPress-based applications against injection attacks.