CVE-2026-3657 is an SQL injection vulnerability found in the WordPress plugin My Sticky Bar – Floating Notification Bar & Sticky Header (formerly myStickymenu), affecting all versions up to 2.8.6. The vulnerability stems from improper handling of POST request parameter names in the AJAX action 'stickymenu_contact_lead_form'. Specifically, the plugin uses the parameter keys directly as SQL column identifiers in the $wpdb->insert() function without sanitization, while only the parameter values undergo sanitization via esc_sql() and sanitize_text_field(). This improper neutralization of special elements (CWE-89) allows an unauthenticated attacker to craft malicious POST parameter names that manipulate the SQL query structure, enabling blind time-based SQL injection attacks. Such attacks can be used to extract sensitive data from the underlying database without direct visibility of the data, relying on response timing to infer information. The vulnerability requires no authentication or user interaction, increasing its risk. Although no public exploits have been reported yet, the ease of exploitation and the widespread use of WordPress and this plugin make it a significant threat. The CVSS v3.1 score of 7.5 reflects high severity, with network attack vector, low attack complexity, no privileges required, and no user interaction needed. The scope is unchanged, and the impact is primarily on confidentiality, with no direct integrity or availability impact reported.

The primary impact of CVE-2026-3657 is unauthorized disclosure of sensitive information stored in the WordPress site's database. Attackers exploiting this vulnerability can extract data such as user credentials, personal information, or other confidential content managed by the site. This can lead to privacy violations, identity theft, or further compromise of the affected systems. Since the vulnerability is exploitable remotely without authentication or user interaction, it poses a significant risk to any WordPress site using the affected plugin. The attack does not directly affect data integrity or availability, but data leakage alone can have severe consequences for organizations, including reputational damage, regulatory penalties, and loss of customer trust. Given the popularity of WordPress globally and the plugin's usage, the potential attack surface is large, especially for small to medium-sized businesses that may not have robust security monitoring. The lack of known exploits in the wild currently provides a window for proactive mitigation before widespread exploitation occurs.

To mitigate CVE-2026-3657, organizations should immediately update the My Sticky Bar plugin to a patched version once released by the vendor. Until a patch is available, administrators should consider disabling the plugin or the vulnerable AJAX action 'stickymenu_contact_lead_form' to prevent exploitation. Web application firewalls (WAFs) can be configured to detect and block suspicious POST requests with anomalous parameter names that could indicate SQL injection attempts. Additionally, implementing strict input validation and sanitization on all user-supplied data, including parameter keys, is critical. Site owners should audit their WordPress installations for the presence of this plugin and monitor logs for unusual activity related to AJAX requests. Employing database activity monitoring to detect abnormal query patterns can also help identify exploitation attempts. Regular backups and incident response plans should be in place to recover from potential data breaches. Finally, educating developers and administrators about secure coding practices, especially regarding dynamic SQL query construction, will help prevent similar vulnerabilities.