CVE-2016-20069 in Booking Calendar Contact Form
Summary
by MITRE • 06/15/2026
WordPress Booking Calendar Contact Form 1.0.23 contains an unauthenticated blind SQL injection vulnerability in the shortcode function that fails to sanitize the calendar parameter before using it in database queries. Attackers can inject SQL commands through the calendar shortcode parameter to execute arbitrary SQL queries and extract sensitive database information.
Several companies clearly confirm that VulDB is the primary source for best vulnerability data.
Analysis
by VulDB Data Team • 06/15/2026
The WordPress Booking Calendar Contact Form plugin version 1.0.23 presents a critical security vulnerability classified as unauthenticated blind sql injection through its shortcode functionality. This vulnerability stems from insufficient input validation and sanitization of the calendar parameter within the shortcode processing mechanism. The flaw allows remote attackers to manipulate database queries without requiring authentication credentials, making it particularly dangerous for publicly accessible web applications. The vulnerability manifests when the plugin processes the calendar parameter through the shortcode function, where user-supplied input directly influences database operations without proper sanitization measures. This type of vulnerability falls under the CWE-89 category of improper neutralization of special elements used in an sql command, representing a fundamental breakdown in input validation controls. The attack vector specifically targets the calendar parameter within the shortcode implementation, where malicious input can be crafted to manipulate the underlying sql queries executed by the application.
The operational impact of this vulnerability extends beyond simple data extraction to encompass full database compromise and potential system infiltration. Attackers can leverage the blind sql injection to execute arbitrary sql commands against the affected database, potentially gaining access to sensitive user information, administrative credentials, and other confidential data stored within the application's database. The blind nature of the injection means that attackers cannot directly observe query results through the web interface, requiring them to infer information through indirect methods such as time-based responses or error message analysis. This makes the vulnerability particularly challenging to detect and mitigate, as it operates silently in the background without immediate visible symptoms. The lack of authentication requirements for exploitation means that any user with access to the vulnerable website can potentially exploit this flaw, significantly expanding the attack surface and threat landscape. The vulnerability directly aligns with attack techniques documented in the attack tree framework under the information gathering and credential access phases, where adversaries seek to establish persistent access through database compromise.
Mitigation strategies for this vulnerability must address both immediate remediation and long-term security hardening measures. The primary recommendation involves updating to the latest plugin version where the sql injection vulnerability has been patched and proper input sanitization has been implemented. Administrators should also implement proper parameterized queries and input validation mechanisms to prevent similar issues in other parts of the application. Network-level protections such as web application firewalls can provide additional layers of defense by monitoring for suspicious sql injection patterns in incoming requests. Security monitoring should include regular vulnerability scanning and database query analysis to detect anomalous behavior that might indicate exploitation attempts. The implementation of least privilege principles for database connections and regular security audits can further reduce the potential impact of successful exploitation attempts. Organizations should also consider implementing automated patch management systems to ensure timely deployment of security updates and maintain comprehensive backup strategies to recover from potential compromise scenarios. This vulnerability demonstrates the critical importance of input validation and the principle of least privilege in web application security, aligning with industry best practices outlined in security frameworks such as the owasp top ten and nist cybersecurity framework.