CVE-2023-4597 in Slimstat Analytics Plugin
Summary
by MITRE • 08/30/2023
The Slimstat Analytics plugin for WordPress is vulnerable to Stored Cross-Site Scripting via the 'slimstat' shortcode in versions up to, and including, 5.0.9 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 • 04/10/2026
The Slimstat Analytics plugin for WordPress presents a critical stored cross-site scripting vulnerability identified as CVE-2023-4597 affecting versions through 5.0.9. This vulnerability stems from inadequate input sanitization and output escaping mechanisms within the plugin's shortcode implementation, specifically the 'slimstat' shortcode. The flaw allows authenticated attackers who possess contributor-level permissions or higher to inject malicious JavaScript code into WordPress pages through the plugin's shortcode functionality. The vulnerability operates as a stored XSS attack because the malicious scripts are permanently stored within the WordPress database and executed each time affected pages are accessed by any user, including administrators. This creates a persistent threat vector that can compromise user sessions and potentially escalate to full system compromise. The vulnerability is particularly concerning given that contributor-level users typically have significant privileges within WordPress environments, including the ability to create and edit posts, upload files, and manage comments. The attack requires minimal privileges but can result in widespread impact across the entire WordPress installation.
The technical nature of this vulnerability aligns with CWE-79 which describes Cross-Site Scripting flaws, specifically the stored variant where malicious scripts are stored on the server and executed when other users access compromised pages. The root cause lies in the plugin's failure to properly sanitize user-supplied attributes passed to the slimstat shortcode, combined with insufficient output escaping when rendering these attributes in the HTML output. This dual failure creates an exploitable condition where attacker-controlled input can bypass security controls and execute arbitrary code within the browser context of affected users. The vulnerability demonstrates poor input validation practices and highlights the importance of proper context-specific output escaping in web applications. The attack vector is particularly insidious because it leverages legitimate plugin functionality, making it harder for security monitoring systems to detect the malicious activity as it appears to be normal plugin usage.
The operational impact of CVE-2023-4597 extends beyond simple script execution to potentially enable more sophisticated attacks including session hijacking, credential theft, and privilege escalation within the WordPress environment. When authenticated users access pages containing the malicious scripts, their browser sessions can be compromised, allowing attackers to perform actions with the privileges of those users. This could lead to unauthorized content modification, data exfiltration, or even complete system compromise if administrators are among the affected users. The persistent nature of stored XSS means that the attack remains active until the malicious content is removed from the database, potentially affecting all users who access the compromised pages. Organizations may face reputational damage if users' sessions are compromised, and the attack could be used to spread malware or conduct phishing operations against the WordPress site's visitors. The vulnerability also impacts the integrity of the WordPress installation, as attackers can manipulate content and user experiences through the injected scripts.
Mitigation strategies for CVE-2023-4597 should prioritize immediate plugin updates to versions that address the vulnerability, as the vendor has likely released patches to fix the input sanitization and output escaping issues. Organizations should implement strict access controls to limit contributor-level permissions to trusted users only, reducing the attack surface available to potential adversaries. Network-based security controls such as web application firewalls should be configured to monitor for suspicious shortcode usage patterns and malformed script injections. Regular security audits of WordPress plugins should include verification of input sanitization practices and output escaping mechanisms. The principle of least privilege should be enforced by restricting user permissions to the minimum necessary for their roles, and regular monitoring of user activities should be implemented to detect anomalous behavior that might indicate exploitation attempts. Additionally, implementing Content Security Policy headers can provide an additional layer of protection against script execution, though this should complement rather than replace proper input validation. Security teams should also consider implementing automated vulnerability scanning tools that can detect the presence of known vulnerable plugins within their WordPress environments.