CVE-2024-4386 is a stored cross-site scripting vulnerability identified in the Gallery Block (Meow Gallery) plugin for WordPress, versions up to and including 5.1.3. The root cause is improper neutralization of input during web page generation, specifically insufficient sanitization and escaping of the 'data_atts' parameter. This flaw allows authenticated users with contributor-level permissions or higher to inject arbitrary JavaScript code into pages rendered by the plugin. When other users access these pages, the injected scripts execute in their browsers, potentially enabling session hijacking, privilege escalation, or unauthorized actions within the context of the victim’s session. The vulnerability is classified under CWE-79 and has a CVSS v3.1 base score of 6.4, reflecting medium severity. The attack vector is network-based with low attack complexity, requiring privileges but no user interaction beyond page access. The scope is changed because the vulnerability affects other users beyond the attacker. No known exploits are currently reported in the wild. The plugin is widely used in WordPress environments, which are popular globally, increasing the potential attack surface. The vulnerability highlights the importance of rigorous input validation and output encoding in web applications, especially in plugins that accept user-generated content or parameters.

The primary impact of CVE-2024-4386 is on confidentiality and integrity, as attackers can execute arbitrary scripts in the context of other users’ browsers. This can lead to theft of session cookies, enabling account takeover or unauthorized actions on affected WordPress sites. Since the vulnerability is stored XSS, the malicious payload persists on the server and affects all users who visit the compromised page, increasing the attack’s reach. The requirement for contributor-level permissions limits exploitation to authenticated users, but many WordPress sites allow contributors or editors, especially in multi-author blogs or community sites. The vulnerability does not affect availability directly but can facilitate further attacks that degrade service or compromise site integrity. Organizations relying on the Meow Gallery plugin for content display risk reputational damage, data breaches, and potential compliance violations if user data is compromised. The medium CVSS score reflects moderate risk but should not be underestimated given the widespread use of WordPress and the ease of exploitation once authenticated access is obtained.

1. Immediately restrict contributor-level and higher permissions to trusted users only, minimizing the risk of malicious input injection. 2. Monitor and audit user activity logs for suspicious behavior, especially around content creation and editing involving the Meow Gallery plugin. 3. Apply strict input validation and output escaping for the 'data_atts' parameter if custom code or temporary patches are possible before an official update is released. 4. Regularly update the Meow Gallery plugin to the latest version once the vendor releases a patch addressing this vulnerability. 5. Employ Web Application Firewalls (WAFs) with rules to detect and block common XSS payloads targeting the plugin’s parameters. 6. Educate site administrators and content contributors about the risks of XSS and safe content handling practices. 7. Conduct periodic security assessments and penetration testing focused on WordPress plugins and user input handling. 8. Consider implementing Content Security Policy (CSP) headers to mitigate the impact of potential XSS exploitation by restricting script execution sources.