CVE-2026-90943 in filament-comments
Summary
by MITRE • 09/14/2026
parallax filament-comments through 3.0.0 contains a stored cross-site scripting vulnerability in comment body rendering that allows authenticated panel users to inject malicious scripts. Attackers can store XSS payloads in comment bodies that execute in the browsers of other users viewing those comments, including administrators, enabling session token theft and unauthorized actions.
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Analysis
by VulDB Data Team • 09/14/2026
The Parallax filament-comments package version 3.0.0 is affected by a stored cross-site scripting vulnerability within its comment body rendering mechanism. This security flaw arises from insufficient sanitization or encoding of user-supplied input when comments are displayed to other users on the platform. Unlike reflected XSS, where malicious scripts are executed immediately through a crafted link, this vulnerability allows an attacker to persistently store harmful JavaScript code in the database via the comment field. When another user, including those with administrative privileges, views the affected page containing the compromised comment, their browser executes the injected script automatically without further interaction from the victim. This persistence makes stored XSS particularly dangerous as it can affect multiple users over time and does not require social engineering to trigger beyond initial access to the vulnerable module.
The operational impact of this vulnerability is severe due to the potential for session hijacking and unauthorized administrative actions. Since the malicious script executes in the context of the victim's browser, it has full access to cookies, local storage, and other sensitive data associated with the current session. An attacker can exploit this to steal authentication tokens or session IDs, effectively impersonating the victim user. If an administrator views a comment containing such a payload, the attacker gains elevated privileges within the application. This could lead to complete compromise of the web application's integrity, allowing for data exfiltration, defacement, or further lateral movement into backend systems depending on the administrative capabilities exposed through the stolen session.
From a classification perspective, this vulnerability aligns with CWE-79 Improper Neutralization of Input During Web Page Generation commonly known as Cross-site Scripting and specifically falls under Stored XSS variants where input is not validated before storage in a database or persistent store. In terms of attack tactics, it maps to the MITRE ATT&CK framework technique T1059 Command and Scripting Interpreter via browser-based execution, facilitating credential access through T1539 Steal Web Session Cookie. The vulnerability highlights critical failures in input validation at both storage and display layers, emphasizing that trust must not be placed on data simply because it originated from an authenticated user within the same application context.
Mitigation strategies should focus on implementing robust output encoding for all dynamic content rendered to the browser, ensuring that special characters are converted into their HTML entity equivalents before being displayed in comment bodies. Developers must also enforce strict input validation and sanitization at the point of entry to reject or neutralize potentially dangerous script tags and event handlers. Additionally, deploying a Content Security Policy header can significantly reduce the impact by restricting the sources from which scripts can be loaded and executed. Regular security audits and static code analysis tools configured to detect XSS patterns are essential for identifying such flaws early in the development lifecycle before deployment to production environments.