CVE-2023-6994 in List Category Posts Plugin
Summary
by MITRE • 01/11/2024
The List category posts plugin for WordPress is vulnerable to Stored Cross-Site Scripting via the plugin's 'catlist' shortcode in all versions up to, and including, 0.89.3 due to insufficient input sanitization and output escaping on user supplied attributes. This makes it possible for authenticated attackers with contributor-level and above permissions to inject arbitrary web scripts in pages that will execute whenever a user accesses an injected page.
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Analysis
by VulDB Data Team • 04/11/2026
The vulnerability identified as CVE-2023-6994 affects the List category posts plugin for WordPress, specifically targeting versions up to and including 0.89.3. This represents a critical security flaw that enables attackers to execute malicious code through a stored cross-site scripting vector. The vulnerability resides within the plugin's 'catlist' shortcode implementation, which fails to properly sanitize or escape user-supplied input parameters. The flaw allows authenticated attackers who possess contributor-level permissions or higher to inject malicious scripts that persist in the system and execute whenever affected pages are accessed by other users. This creates a persistent threat that can compromise user sessions and potentially lead to broader system exploitation.
The technical nature of this vulnerability aligns with CWE-79, which describes Cross-Site Scripting flaws occurring when user-provided data is not properly sanitized before being rendered in web pages. The vulnerability specifically exploits insufficient input sanitization and output escaping mechanisms within the plugin's shortcode processing logic. When administrators or contributors create posts or pages using the catlist shortcode with malicious attributes, the plugin fails to validate or escape these inputs appropriately. The stored nature of this XSS means that the malicious scripts are saved in the database and executed each time the affected content is rendered, making it particularly dangerous as it can affect multiple users over time without requiring repeated exploitation attempts.
The operational impact of this vulnerability extends beyond simple script execution, as it creates opportunities for attackers to escalate privileges, steal user credentials, or manipulate content. Contributors with access to the WordPress admin interface can leverage this vulnerability to inject scripts that could redirect users to malicious sites, steal cookies, or even modify content in ways that persist across multiple user sessions. The vulnerability's accessibility to users with contributor-level permissions significantly increases the attack surface, as many WordPress installations have multiple contributors who may not be adequately monitored for malicious activity. This makes the vulnerability particularly concerning in multi-user environments where contributor access is more common.
Mitigation strategies for CVE-2023-6994 should begin with immediate plugin updates to versions that address the identified XSS vulnerability. Organizations should also implement network monitoring to detect potential exploitation attempts and consider implementing Content Security Policy headers to reduce the impact of successful XSS attacks. Regular security audits of installed plugins and themes should be conducted to identify similar vulnerabilities in other components. Additionally, implementing proper access controls and privilege management can limit the potential damage from compromised contributor accounts. The vulnerability demonstrates the importance of input validation and output escaping practices in web applications, reinforcing principles from the OWASP Top Ten and NIST cybersecurity guidelines that emphasize proper sanitization of user inputs to prevent injection attacks. Organizations should also consider implementing automated vulnerability scanning tools that can detect such issues in their WordPress installations and maintain up-to-date security patches for all web application components.