CVE-2025-23909 in Compare Ninja Plugin
Summary
by MITRE • 01/16/2025
Improper Neutralization of Input During Web Page Generation ('Cross-site Scripting') vulnerability in Common Ninja Compare Ninja allows Stored XSS.This issue affects Compare Ninja: from n/a through 2.1.0.
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Analysis
by VulDB Data Team • 02/10/2025
The vulnerability identified as CVE-2025-23909 represents a critical cross-site scripting flaw within the Compare Ninja plugin for WordPress, specifically impacting versions ranging from an unspecified initial version through 2.1.0. This weakness falls under the category of improper input neutralization during web page generation, creating a persistent security risk that allows attackers to inject malicious scripts into web pages viewed by other users. The vulnerability stems from inadequate sanitization of user-supplied data that is subsequently rendered in web page contexts without proper escaping or encoding mechanisms.
The technical implementation of this stored cross-site scripting vulnerability occurs when user input intended for comparison functionality is not properly validated or escaped before being stored in the database and subsequently displayed in web pages. This creates a persistent vector where malicious scripts can be injected during the content creation process and then executed whenever legitimate users view the affected pages. The flaw operates at the application layer where user-generated content flows through the application's processing pipeline without adequate security controls to prevent script injection attacks. According to CWE classification, this vulnerability maps to CWE-79 which specifically addresses improper neutralization of input during web page generation, making it a direct instance of web application input validation and output encoding failures.
The operational impact of this vulnerability extends beyond simple script execution as it enables attackers to potentially hijack user sessions, steal sensitive information, perform unauthorized actions on behalf of victims, and manipulate the functionality of the affected website. When exploited, stored XSS attacks can lead to complete compromise of user accounts, especially if the targeted users include administrators or privileged personnel. The persistent nature of stored XSS means that once the malicious payload is injected, it remains active until manually removed from the database, providing attackers with extended opportunities for exploitation. This vulnerability directly aligns with ATT&CK technique T1531 which covers "Modify Application Configuration" and T1059.001 which addresses "Command and Scripting Interpreter" through the execution of malicious scripts in the victim's browser context.
Mitigation strategies for CVE-2025-23909 should prioritize immediate patching of the Compare Ninja plugin to version 2.1.1 or later, as this represents the first fixed release addressing the stored XSS vulnerability. Organizations should implement comprehensive input validation and output encoding mechanisms throughout their web applications, ensuring that all user-supplied data is properly sanitized before storage and rendering. Security measures should include implementing Content Security Policy headers to limit script execution contexts, employing proper HTML escaping for dynamic content, and conducting regular security audits of third-party plugins. Additionally, administrators should consider implementing web application firewalls to detect and block suspicious input patterns, while establishing monitoring procedures to identify potential exploitation attempts. The remediation process must also include thorough testing of the patched version to ensure that the fix does not introduce regressions in functionality while maintaining the security improvements necessary to prevent future exploitation attempts.