CVE-2023-48827 in Time Slots Booking Calendar
Summary
by MITRE • 12/07/2023
Time Slots Booking Calendar 4.0 is vulnerable to Multiple HTML Injection issues via the name, plugin_sms_api_key, plugin_sms_country_code, calendar_id, title, country name, or customer_name parameter.
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Analysis
by VulDB Data Team • 03/01/2026
The Time Slots Booking Calendar plugin version 4.0 presents a significant security vulnerability classified as multiple HTML injection flaws that can be exploited through several input parameters including name, plugin_sms_api_key, plugin_sms_country_code, calendar_id, title, country name, or customer_name. This vulnerability falls under the category of cross-site scripting attacks and represents a critical risk to web applications utilizing this calendar plugin. The flaw allows attackers to inject malicious HTML content into the application's output, potentially leading to unauthorized actions being performed on behalf of users or sensitive data extraction. The vulnerability stems from insufficient input validation and output sanitization within the plugin's processing logic, where user-supplied data is directly incorporated into web responses without proper encoding or filtering mechanisms. This weakness creates an environment where malicious actors can manipulate the application's behavior by injecting crafted HTML code through the identified parameters, which are commonly used in booking and calendar management operations.
The technical exploitation of this vulnerability occurs when an attacker submits malicious HTML content through any of the vulnerable parameters mentioned in the CVE description. The plugin fails to properly sanitize or encode user input before rendering it in the web interface, allowing HTML tags and scripts to be executed within the context of the victim's browser session. This injection can occur in various contexts including user interface elements, database storage, or API responses, depending on how the application processes these parameters. The vulnerability is particularly concerning because it affects multiple input vectors, increasing the attack surface and making it more difficult for administrators to fully mitigate the issue by addressing only a single parameter. The impact extends beyond simple script execution to potentially enable more sophisticated attacks such as session hijacking, credential theft, or redirection to malicious websites, as the injected HTML can leverage the victim's authenticated session to perform unauthorized operations within the calendar application.
The operational impact of this vulnerability extends beyond immediate security concerns to encompass potential business disruption and data compromise. Organizations using the Time Slots Booking Calendar plugin may experience unauthorized access to booking data, customer information, or calendar events, as attackers can manipulate the application to display malicious content or redirect users to phishing sites. The vulnerability can be exploited by attackers with minimal technical expertise, as it does not require complex attack vectors or specific conditions to be successful. This makes it particularly dangerous in environments where the plugin is widely used or integrated into critical business processes. The injection of malicious HTML content could also be used to deface web pages, steal session cookies, or establish persistent backdoors within the application environment. According to the CWE database, this vulnerability aligns with CWE-79 which describes cross-site scripting flaws, and it may also relate to CWE-116 for improper neutralization of special elements used in HTML markup. The attack surface is further expanded by the fact that this vulnerability affects parameters commonly used in booking systems, making it a prime target for attackers seeking to compromise customer relationship management or appointment scheduling systems.
Mitigation strategies for this vulnerability should focus on comprehensive input validation and output encoding mechanisms. Administrators should immediately update to the latest version of the Time Slots Booking Calendar plugin where this vulnerability has been patched. Until such updates are available, implementing proper input sanitization techniques is essential, including the use of HTML entity encoding for all user-supplied data before rendering in web interfaces. The implementation of Content Security Policy headers can provide additional protection against script execution, while regular security audits should be conducted to identify other potential injection points within the application. According to ATT&CK framework, this vulnerability maps to T1059.007 for script injection techniques and T1566 for social engineering attacks that could leverage the compromised calendar functionality. Organizations should also consider implementing web application firewalls to detect and block malicious input patterns, while establishing monitoring protocols to identify unusual activity patterns that might indicate exploitation attempts. Regular security training for developers and administrators on secure coding practices remains crucial to prevent similar vulnerabilities in custom implementations and third-party integrations that may be affected by similar HTML injection flaws.