CVE-2024-13581 identifies a stored Cross-Site Scripting (XSS) vulnerability in the Simple Charts plugin for WordPress, developed by supporthost. The flaw exists in all versions up to and including 1.0 due to improper neutralization of user input in the 'simple_chart' shortcode. Specifically, the plugin fails to adequately sanitize and escape user-supplied attributes before rendering them on web pages. This allows authenticated users with contributor-level permissions or higher to inject arbitrary JavaScript code that is stored persistently within the website's content. When other users access the affected pages, the malicious scripts execute in their browsers, potentially leading to session hijacking, credential theft, or unauthorized actions performed on behalf of the victim. The vulnerability requires no user interaction beyond visiting the compromised page and does not require elevated privileges beyond contributor access, which is commonly granted to content creators on WordPress sites. The CVSS 3.1 base score of 6.4 reflects a medium severity rating, considering the network attack vector, low attack complexity, and the partial impact on confidentiality and integrity without affecting availability. No public exploits have been reported yet, but the vulnerability's presence in a widely used CMS plugin increases the risk of future exploitation. The lack of available patches at the time of reporting necessitates interim mitigations to reduce exposure.

This vulnerability can significantly impact organizations relying on WordPress websites with the Simple Charts plugin installed. Attackers with contributor access can embed malicious scripts that execute in the browsers of site visitors, potentially leading to theft of sensitive information such as authentication cookies, personal data, or administrative credentials. This can result in unauthorized access, defacement, or further compromise of the website and its users. The persistent nature of stored XSS means the malicious code remains active until removed, increasing the window of exposure. For organizations, this can lead to reputational damage, loss of customer trust, and regulatory compliance issues, especially if user data is compromised. Since contributor-level access is often granted to multiple users, insider threats or compromised contributor accounts can be leveraged to exploit this vulnerability. The medium severity rating indicates a moderate but tangible risk that should be addressed promptly to prevent escalation or chaining with other vulnerabilities.

1. Apply patches or updates from the plugin vendor as soon as they become available to address the input sanitization and output escaping flaws. 2. Until patches are released, restrict contributor-level access to trusted users only and review existing contributor accounts for suspicious activity. 3. Implement Web Application Firewall (WAF) rules to detect and block suspicious payloads targeting the 'simple_chart' shortcode parameters. 4. Conduct regular security audits and code reviews of plugins and themes to identify unsafe input handling. 5. Use Content Security Policy (CSP) headers to limit the execution of unauthorized scripts on the website. 6. Educate content contributors about the risks of injecting untrusted content and enforce strict content submission guidelines. 7. Monitor website logs and user activity for signs of exploitation or anomalous behavior. 8. Consider disabling or replacing the Simple Charts plugin with a more secure alternative if immediate patching is not feasible.