CVE-2026-14833 in Lightbox with PhotoSwipe Plugin
Summary
by MITRE • 07/31/2026
The Lightbox with PhotoSwipe WordPress plugin before 5.9.0 does not sanitise or escape a link data attribute before rendering it into the image lightbox caption in the browser, allowing users with author-level access and above (who lack the unfiltered_html capability) to store JavaScript that runs when a visitor or administrator opens the lightbox.
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Analysis
by VulDB Data Team • 07/31/2026
The vulnerability exists within the Lightbox with PhotoSwipe WordPress plugin version 5.8.9 and earlier, where insufficient input sanitization and output escaping mechanisms fail to properly handle user-supplied data in the link data attribute before rendering it into image lightbox captions. This represents a classic cross-site scripting vulnerability that allows authenticated attackers with author-level privileges or higher to inject malicious javascript code into the plugin's output. The flaw specifically occurs during the rendering process of lightbox captions where the plugin fails to sanitize user-provided link attributes, creating an execution path for malicious scripts when visitors or administrators interact with the affected lightbox functionality.
The technical nature of this vulnerability aligns with CWE-79 - Cross-site Scripting and falls under the broader category of improper input validation and output escaping issues. Attackers can exploit this weakness by crafting malicious data attributes containing javascript payloads within the link fields that are subsequently rendered into the lightbox captions. Even though these attackers lack the unfiltered_html capability which would normally prevent such injections, the plugin's failure to properly sanitize the data attribute before output means that legitimate content with embedded scripts can execute in the context of the victim's browser. This presents a significant risk because the attack vector requires only author-level access, which is commonly granted to content creators and contributors who may not be fully trusted within security-sensitive environments.
The operational impact extends beyond simple script execution as it enables persistent cross-site scripting attacks that can compromise user sessions, steal sensitive information, or redirect users to malicious sites. When administrators or visitors open the lightbox containing the malicious data attribute, the stored javascript executes in their browser context, potentially allowing attackers to perform actions such as stealing cookies, modifying page content, or conducting phishing attacks against other users. The vulnerability becomes particularly dangerous in environments where administrators frequently interact with content and may unknowingly trigger the execution of malicious scripts when opening lightbox views. This attack scenario represents a privilege escalation path that can be leveraged for broader compromise beyond just the immediate plugin functionality.
Mitigation strategies must focus on implementing proper input sanitization and output escaping mechanisms throughout the plugin's data handling pipeline. The recommended approach involves applying strict sanitization filters to all user-supplied data attributes before rendering them into HTML output, specifically targeting any javascript protocols or script tags that may be embedded within link data attributes. Additionally, implementing content security policies can provide an additional layer of protection by restricting script execution within the lightbox context. The most effective solution requires updating to version 5.9.0 or later where proper sanitization has been implemented to prevent malicious data from being rendered into the lightbox captions. Organizations should also consider implementing automated scanning tools to detect similar vulnerabilities in other plugins and ensure that all user-generated content undergoes proper validation before being displayed in browser contexts.
This vulnerability demonstrates the critical importance of proper input validation and output escaping in web applications, particularly within content management systems where multiple user roles may interact with plugin functionality. The attack vector highlights how seemingly innocuous data fields can become entry points for sophisticated attacks when proper sanitization mechanisms are not implemented. Security practitioners should treat this as a reminder that even low-privilege authenticated users can pose significant threats if plugins fail to properly validate and escape user input before rendering it in browser contexts, making comprehensive security testing and regular updates essential components of any WordPress security strategy.