CVE-2022-4035 in Appointment Hour Booking Plugin
Summary
by MITRE • 11/30/2022
The Appointment Hour Booking plugin for WordPress is vulnerable to iFrame Injection via the ‘email’ or general field parameters in versions up to, and including, 1.3.72 due to insufficient input sanitization and output escaping that makes injecting iFrame tags possible. This makes it possible for unauthenticated attackers to inject iFrames when submitting a booking that will execute whenever a user accesses the injected booking details page.
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Analysis
by VulDB Data Team • 04/09/2026
The CVE-2022-4035 vulnerability affects the Appointment Hour Booking plugin for WordPress, a widely used tool for managing online appointments and bookings. This particular flaw exists in versions up to and including 1.3.72, making it a significant concern for WordPress site administrators who rely on this plugin for their booking operations. The vulnerability stems from inadequate input sanitization and output escaping mechanisms within the plugin's codebase, creating a pathway for malicious actors to exploit the system through carefully crafted inputs.
The technical flaw manifests through the manipulation of the 'email' or general field parameters during the booking submission process. When users submit booking information through the plugin's interface, the application fails to properly sanitize or escape user-provided data before rendering it on the booking details page. This insufficient validation allows attackers to inject malicious iFrame content directly into the plugin's output. The vulnerability is classified as an iFrame injection attack, which falls under the CWE-79 category of Cross-Site Scripting (XSS) vulnerabilities, specifically representing a reflected XSS variant where the malicious payload is reflected back to users through the application's response.
The operational impact of this vulnerability is substantial and multifaceted. Unauthenticated attackers can exploit this weakness to inject iFrames that execute whenever legitimate users access the booking details page containing the malicious content. This creates a persistent threat vector where attackers can perform various malicious activities including credential theft, defacement of booking pages, redirection to malicious websites, or even the execution of additional malicious scripts. The attack requires minimal privileges and can affect any user who views the compromised booking information, making it particularly dangerous in environments where multiple users access booking management interfaces. From an attacker's perspective, this vulnerability aligns with ATT&CK technique T1566.001 for Initial Access through Spearphishing Attachment and T1584.004 for Compromise of Third-Party Applications, as it exploits a third-party plugin to gain unauthorized access to user sessions.
The security implications extend beyond simple script injection, as the iFrame injection can be leveraged to perform more sophisticated attacks. Attackers can use the injected iFrames to redirect users to phishing pages that mimic legitimate booking interfaces, harvest login credentials, or even deploy additional malware through drive-by download techniques. The vulnerability is particularly concerning because it affects the core booking functionality of the plugin, meaning that any booking information submitted through the vulnerable version could become a vector for malicious activity. Organizations using this plugin may experience reputational damage, data breaches, and potential regulatory compliance issues if user information is compromised through this attack vector. The lack of authentication requirements for exploitation makes it especially dangerous as it can be executed by anyone with access to the booking submission interface.
Mitigation strategies for this vulnerability should include immediate plugin updates to versions that address the sanitization and escaping issues. System administrators should also implement additional security measures such as input validation at the application level, output encoding for all user-provided content, and regular security audits of third-party plugins. The implementation of Content Security Policy (CSP) headers can provide an additional layer of protection by restricting the sources from which iFrames can be loaded. Organizations should also consider implementing web application firewalls to detect and block suspicious input patterns. Regular monitoring of plugin updates and security advisories from WordPress.org is essential to maintain protection against similar vulnerabilities. From a compliance standpoint, this vulnerability highlights the importance of maintaining up-to-date third-party software and implementing proper security controls as required by standards such as ISO 27001 and NIST cybersecurity frameworks. The vulnerability serves as a reminder of the critical importance of proper input validation and output escaping in web applications, particularly those handling user-generated content.