CVE-2025-23652 in Add Custom Content After Post Plugin
Summary
by MITRE • 02/14/2025
Improper Neutralization of Input During Web Page Generation ('Cross-site Scripting') vulnerability in NotFound Add custom content after post allows Reflected XSS. This issue affects Add custom content after post: from n/a through 1.0.
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Analysis
by VulDB Data Team • 02/14/2025
The CVE-2025-23652 vulnerability represents a critical cross-site scripting flaw in the NotFound Add custom content after post plugin, specifically impacting versions ranging from n/a through 1.0. This vulnerability falls under the CWE-79 category of Improper Neutralization of Input During Web Page Generation, which is a fundamental weakness in web application security that enables malicious actors to inject client-side scripts into web pages viewed by other users. The vulnerability manifests as a reflected cross-site scripting issue, meaning that malicious input is immediately reflected back to users without proper sanitization or encoding, creating an exploitable vector for various attack scenarios.
The technical implementation of this flaw occurs within the plugin's web page generation process where user input is not adequately neutralized before being rendered in the browser context. When a user visits a page that includes improperly handled input parameters, the malicious script code becomes part of the dynamically generated HTML content, allowing attackers to execute arbitrary JavaScript in the victim's browser. This reflected nature means that the attack payload is typically delivered through a malicious URL containing the XSS payload, which is then reflected back by the vulnerable application when the user clicks the link. The vulnerability specifically affects the plugin's functionality for adding custom content after posts, suggesting that any input field or parameter associated with post content manipulation could serve as an attack vector.
The operational impact of this vulnerability extends beyond simple script execution, as it can enable attackers to perform a wide range of malicious activities including session hijacking, credential theft, redirection to malicious sites, and data exfiltration from authenticated users. Attackers can leverage this vulnerability to steal cookies, modify page content, inject malicious advertisements, or even redirect users to phishing sites that appear legitimate. The reflected nature of the vulnerability means that the attack requires user interaction, typically through social engineering techniques to convince victims to click malicious links. However, the severity is amplified because the vulnerability affects a plugin that is likely used by multiple websites, potentially allowing for mass exploitation across various WordPress installations. This type of vulnerability is particularly dangerous in environments where administrators and users have elevated privileges, as attackers could potentially escalate their privileges or access sensitive administrative functions.
Mitigation strategies for CVE-2025-23652 should prioritize immediate remediation through plugin updates to versions that properly sanitize input parameters and implement proper output encoding. Organizations should implement comprehensive input validation and output encoding mechanisms that follow the OWASP XSS Prevention Cheat Sheet guidelines, ensuring that all user-supplied data is properly escaped before being rendered in web pages. The implementation of Content Security Policy headers can provide additional defense-in-depth measures by restricting the sources from which scripts can be executed. Security teams should also consider deploying web application firewalls that can detect and block common XSS payload patterns. Regular security audits and penetration testing should be conducted to identify similar vulnerabilities in other plugins and themes. The vulnerability highlights the importance of maintaining up-to-date WordPress installations and plugins, as well as implementing proper security monitoring to detect potential exploitation attempts. Additionally, user education regarding the risks of clicking suspicious links and the importance of verifying website authenticity can help reduce the success rate of social engineering attacks that leverage this vulnerability.