CVE-2023-48825 in Availability Booking Calendar
Summary
by MITRE • 12/07/2023
Availability Booking Calendar 5.0 is vulnerable to Multiple HTML Injection issues via SMS API Key or Default Country Code.
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Analysis
by VulDB Data Team • 03/01/2026
The Availability Booking Calendar plugin version 5.0 presents a significant security vulnerability that falls under the category of multiple HTML injection flaws within its SMS API key and default country code functionality. This vulnerability represents a critical weakness in the plugin's input validation mechanisms, allowing malicious actors to inject arbitrary HTML content into the system's response handling processes. The flaw specifically manifests when the plugin processes SMS API keys or default country code parameters without proper sanitization, creating an attack surface that could be exploited to manipulate the application's behavior and potentially compromise user data integrity.
The technical implementation of this vulnerability stems from insufficient validation and sanitization of user-supplied input within the plugin's backend processing logic. When administrators or users provide SMS API keys or default country code values, the system fails to properly escape or validate these inputs before incorporating them into HTML responses or database storage. This oversight creates an environment where attackers can craft malicious input sequences that, when processed by the plugin, result in the injection of HTML tags, scripts, or other malicious content. The vulnerability is particularly concerning because it operates at the point where user input transitions into system response handling, making it difficult to detect and trace through standard security monitoring systems.
The operational impact of this vulnerability extends beyond simple HTML injection, potentially enabling attackers to perform cross-site scripting attacks that could lead to session hijacking, data exfiltration, or unauthorized administrative access. When combined with other potential attack vectors within the same plugin ecosystem, this vulnerability could serve as a foothold for more sophisticated attacks targeting the broader WordPress installation. The availability calendar plugin's role in handling booking data and user information makes it a particularly attractive target for threat actors seeking to exploit weaknesses in the system's data handling processes. This vulnerability directly impacts the plugin's ability to maintain data integrity and user trust, potentially leading to service disruption and reputation damage for affected organizations.
Mitigation strategies for this vulnerability should focus on implementing comprehensive input validation and sanitization measures across all user-supplied parameters within the plugin's SMS API key and default country code functionality. Security professionals should immediately patch the affected plugin version to address the HTML injection flaws, while also implementing proper HTML escaping mechanisms for all dynamic content generation processes. Organizations should consider implementing web application firewalls to monitor and block suspicious input patterns, while also conducting thorough security assessments of their WordPress installations to identify similar vulnerabilities in other plugins or themes. The remediation process should include comprehensive testing to ensure that all input handling paths properly sanitize user data before processing, and that any previously injected malicious content is properly removed from the system. This vulnerability demonstrates the critical importance of input validation in preventing HTML injection attacks and aligns with common security practices outlined in the CWE database under category 79 for cross-site scripting vulnerabilities.