CVE-2024-8547 is a stored Cross-Site Scripting (XSS) vulnerability identified in the Simple Popup Plugin developed by grimmdude for WordPress. The vulnerability exists due to improper neutralization of input during web page generation, specifically within the plugin's [popup] shortcode. The plugin fails to adequately sanitize and escape user-supplied attributes, allowing authenticated users with contributor-level permissions or higher to inject arbitrary JavaScript code into pages. This malicious code is stored persistently and executed in the browsers of any users who visit the compromised pages, potentially leading to session hijacking, privilege escalation, or unauthorized actions performed on behalf of the victim. The vulnerability affects all versions of the plugin up to and including version 4.5. The CVSS 3.1 base score is 6.4, reflecting a medium severity with a network attack vector (AV:N), low attack complexity (AC:L), requiring privileges (PR:L), no user interaction (UI:N), and a scope change (S:C) that affects confidentiality and integrity partially (C:L/I:L) but not availability (A:N). No public exploits have been reported yet, but the vulnerability poses a significant risk due to the widespread use of WordPress and the plugin's popularity. The flaw is classified under CWE-79, which covers improper neutralization of input leading to XSS attacks. The vulnerability was published on September 28, 2024, with the Wordfence team as the assigner. No official patches have been linked yet, so mitigation relies on access control and input validation measures.

The primary impact of CVE-2024-8547 is the potential for attackers with contributor-level access to inject persistent malicious scripts into WordPress sites using the Simple Popup Plugin. This can lead to session hijacking, theft of sensitive user information, unauthorized actions performed with victim privileges, and potential spread of malware or phishing attacks. Since the vulnerability allows script execution in the context of the affected site, it compromises the confidentiality and integrity of user data and site content. Although availability is not directly impacted, the reputational damage and loss of user trust can be significant. Organizations relying on this plugin, especially those with multiple contributors or editors, face increased risk of insider threats or compromised contributor accounts being leveraged for exploitation. The scope of affected systems is broad due to WordPress's global market share and the plugin's usage. Without proper mitigation, attackers can exploit this vulnerability remotely over the network without requiring victim interaction, increasing the likelihood of successful attacks.

1. Immediately restrict contributor-level and higher user permissions to trusted personnel only, minimizing the risk of malicious script injection. 2. Monitor and audit all content created or edited via the Simple Popup Plugin's [popup] shortcode for suspicious or unauthorized script tags or attributes. 3. Implement Web Application Firewall (WAF) rules to detect and block common XSS payloads targeting the plugin's shortcode parameters. 4. Employ Content Security Policy (CSP) headers to limit the execution of inline scripts and restrict script sources to trusted domains. 5. Regularly update the Simple Popup Plugin once an official patch is released by the vendor to address the vulnerability. 6. Consider temporarily disabling or removing the plugin if patching is not immediately possible, especially on high-risk or public-facing sites. 7. Educate contributors about safe content creation practices and the risks of embedding scripts or untrusted code. 8. Use security plugins that provide enhanced input sanitization and output escaping for shortcodes and user-generated content. 9. Conduct periodic security assessments and penetration testing focusing on plugin vulnerabilities and user privilege abuse.