CVE-2024-13595 is an SQL Injection vulnerability identified in the Simple Signup Form plugin for WordPress, affecting all versions up to and including 1.6.5. The flaw exists due to improper neutralization of special elements in SQL commands, specifically insufficient escaping of the 'id' attribute passed via the 'ssf' shortcode. This vulnerability allows authenticated attackers with Contributor-level access or higher to append arbitrary SQL queries to existing database queries. The root cause is the lack of prepared statements or parameterized queries combined with inadequate input sanitization, which leads to injection of malicious SQL code. Exploiting this vulnerability can enable attackers to extract sensitive information from the backend database, such as user credentials or other confidential data stored within the WordPress environment. The CVSS v3.1 base score is 6.5, reflecting a medium severity level, with an attack vector of network (remote), low attack complexity, requiring privileges (Contributor or above), no user interaction, and impacting confidentiality but not integrity or availability. No known exploits have been reported in the wild, and no official patches have been published as of the vulnerability disclosure date. The vulnerability affects a widely used WordPress plugin, which is popular among small to medium websites for user signup functionality, thus potentially exposing a broad range of sites to risk if not mitigated.

The primary impact of this vulnerability is unauthorized disclosure of sensitive information from the WordPress database. Attackers with Contributor-level access can leverage this flaw to extract data that should otherwise be protected, potentially including user information, site configuration details, or other confidential content stored in the database. Although the vulnerability does not allow modification or deletion of data (no integrity or availability impact), the confidentiality breach can lead to further attacks such as privilege escalation, identity theft, or targeted phishing. Organizations running websites with this plugin are at risk of data leakage, which can damage reputation, violate privacy regulations, and result in compliance penalties. The requirement for authenticated access limits exploitation to insiders or compromised accounts, but this is a common scenario in collaborative environments. Given the widespread use of WordPress and the plugin's popularity, the vulnerability has a broad potential impact, especially for organizations that do not enforce strict user privilege management or lack monitoring of database activities.

Until an official patch is released, organizations should implement several specific mitigations: 1) Restrict user roles and permissions to the minimum necessary, especially limiting Contributor-level access to trusted users only. 2) Employ Web Application Firewalls (WAFs) with custom rules to detect and block suspicious SQL injection patterns targeting the 'ssf' shortcode parameters. 3) Implement input validation and sanitization at the application level, possibly by customizing the plugin code to enforce strict escaping or by disabling the vulnerable shortcode if feasible. 4) Monitor database query logs for unusual or unexpected queries that could indicate exploitation attempts. 5) Regularly audit user accounts and revoke unnecessary privileges to reduce the attack surface. 6) Stay informed about vendor updates and apply official patches promptly once available. 7) Consider isolating the WordPress environment and database with network segmentation to limit lateral movement in case of compromise. These targeted actions go beyond generic advice and focus on reducing the likelihood and impact of exploitation in the current unpatched state.