CVE-2025-5035 in Firelight Lightbox Plugin
Summary
by MITRE • 06/27/2025
The Firelight Lightbox WordPress plugin before 2.3.16 does not sanitise and escape title attributes before outputting them in the page, which could allow users with a role as low as contributors to perform stored Cross-Site Scripting attacks.
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Analysis
by VulDB Data Team • 07/01/2025
The Firelight Lightbox WordPress plugin vulnerability CVE-2025-5035 represents a critical stored cross-site scripting flaw that affects versions prior to 2.3.16. This security weakness stems from inadequate input sanitization and output escaping mechanisms within the plugin's handling of title attributes. The vulnerability specifically targets the plugin's failure to properly process user-supplied data before rendering it in web pages, creating an environment where malicious scripts can be persistently injected and executed. The flaw is particularly concerning because it allows users with minimal privileges, including contributors who typically have limited access rights, to exploit this weakness and compromise the security of the entire WordPress installation. This represents a significant elevation of privilege issue where low-privilege users can gain the ability to execute arbitrary code within the context of other users' browsers, potentially leading to session hijacking, data theft, or further exploitation of the compromised systems.
The technical implementation of this vulnerability aligns with CWE-79 which specifically addresses cross-site scripting flaws in web applications. The root cause lies in the plugin's improper handling of user input data where title attributes are directly output to HTML without appropriate sanitization measures. This flaw falls under the category of stored XSS attacks because the malicious payloads are persisted in the database and executed whenever affected pages are loaded, rather than requiring immediate interaction with a malicious link. The vulnerability demonstrates poor input validation and output encoding practices that violate fundamental web security principles. Attackers can leverage this weakness by creating or modifying lightbox elements with malicious script content in their title attributes, which then gets executed when other users view the affected pages, creating a persistent threat that can affect multiple users over time.
The operational impact of CVE-2025-5035 extends beyond simple script execution as it provides attackers with a foothold for more sophisticated attacks within the WordPress environment. Contributors who can create or modify content are able to inject malicious scripts that can steal cookies, session tokens, or other sensitive information from authenticated users. This vulnerability can be exploited to perform account takeover attacks, manipulate content, or redirect users to malicious sites. The persistent nature of stored XSS means that the attack remains active until the malicious code is removed from the database, potentially affecting all users who view the compromised pages. The vulnerability also creates potential for privilege escalation attacks where attackers can use the XSS to gain access to higher-privilege accounts or perform administrative functions. Additionally, the exploitation of this vulnerability can lead to reputational damage for the website owner and potential compliance violations in environments with strict security requirements.
Mitigation strategies for CVE-2025-5035 should prioritize immediate plugin updates to version 2.3.16 or later where the sanitization and escaping issues have been addressed. System administrators should implement comprehensive input validation and output encoding measures across all user-generated content to prevent similar vulnerabilities in other components. The principle of least privilege should be enforced by restricting contributor capabilities to prevent unauthorized access to potentially dangerous plugin features. Security monitoring should include regular scanning for stored XSS vulnerabilities in all installed plugins and themes, with particular attention to any custom modifications that might introduce similar weaknesses. Organizations should also consider implementing content security policies to add an additional layer of protection against script execution. The vulnerability highlights the importance of proper security testing and code review processes, particularly for plugins that handle user input and generate dynamic content. Regular security audits of WordPress installations, including vulnerability assessments of all plugins and themes, should be conducted to identify and remediate similar security weaknesses before they can be exploited by malicious actors. This case demonstrates the critical need for maintaining up-to-date software components and implementing robust security practices throughout the WordPress ecosystem.