CVE-2024-3557 is a stored cross-site scripting (XSS) vulnerability classified under CWE-80 affecting the WP Go Maps plugin for WordPress, previously known as WP Google Maps. The vulnerability exists in all versions up to and including 9.0.36 due to improper neutralization of script-related HTML tags within the plugin's wpgmza shortcode. Specifically, the plugin fails to adequately sanitize and escape user-supplied attributes, allowing authenticated users with contributor-level access or higher to inject arbitrary JavaScript code. When a page containing the injected shortcode is accessed by any user, the malicious script executes in their browser context. This can lead to a range of attacks including session hijacking, unauthorized actions on behalf of users, defacement, or further exploitation of the site. The vulnerability requires authentication but only low-level privileges, making it easier for attackers who have compromised or registered contributor accounts to exploit. The CVSS 3.1 base score of 6.4 reflects a medium severity, with network attack vector, low attack complexity, privileges required, no user interaction, and a scope change due to potential impact beyond the initial component. No public exploits have been reported so far, but the widespread use of WP Go Maps in WordPress sites makes this a significant risk. The issue highlights the importance of proper input validation and output encoding in WordPress plugins, especially those that accept user-generated content or shortcode attributes.

The impact of CVE-2024-3557 is significant for organizations running WordPress sites with the WP Go Maps plugin installed. Successful exploitation allows an attacker with contributor-level access to inject persistent malicious scripts that execute in the browsers of site visitors and administrators. This can lead to session hijacking, theft of sensitive information such as authentication cookies, unauthorized actions performed on behalf of users, and potential site defacement. The vulnerability can also be leveraged as a foothold for further attacks, including privilege escalation or distribution of malware. Since contributor-level access is relatively low privilege, attackers can exploit compromised or malicious contributor accounts, or potentially exploit other vulnerabilities to gain such access. The scope of affected systems is broad given the popularity of WordPress and the WP Go Maps plugin, impacting websites globally across many sectors including e-commerce, media, education, and government. The lack of user interaction requirement increases the risk, as the malicious script executes automatically when the injected page is viewed. Although no known exploits are currently active in the wild, the medium CVSS score and ease of exploitation warrant prompt attention to prevent potential damage.

To mitigate CVE-2024-3557, organizations should take the following specific actions: 1) Immediately update the WP Go Maps plugin to a patched version once available from the vendor to ensure proper input sanitization and output escaping. 2) Restrict contributor-level access strictly to trusted users and review existing contributor accounts for suspicious activity. 3) Implement a web application firewall (WAF) with rules to detect and block malicious shortcode payloads or suspicious script injections targeting the wpgmza shortcode. 4) Employ Content Security Policy (CSP) headers to limit the execution of unauthorized scripts in browsers. 5) Regularly audit and sanitize user-generated content and shortcode attributes before rendering on pages. 6) Monitor logs and site behavior for signs of XSS exploitation, such as unusual script execution or unauthorized actions. 7) Educate site administrators and contributors about the risks of XSS and safe content practices. 8) Consider disabling or limiting the use of shortcodes that accept user input if not essential. These targeted mitigations go beyond generic advice by focusing on access control, plugin updates, and layered defenses specific to the vulnerability vector.