CVE-2024-39910 in decidim
Summary
by MITRE • 09/16/2024
decidim is a Free Open-Source participatory democracy, citizen participation and open government for cities and organizations. The WYSWYG editor QuillJS is subject to potential XSS attach in case the attacker manages to modify the HTML before being uploaded to the server. The attacker is able to change e.g. to if they know how to craft these requests themselves. This issue has been addressed in release version 0.27.7. All users are advised to upgrade. Users unable to upgrade should review the user accounts that have access to the admin panel (i.e. general Administrators, and participatory space's Administrators) and remove access to them if they don't need it. Disable the "Enable rich text editor for participants" setting in the admin dashboard
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Analysis
by VulDB Data Team • 03/10/2025
CVE-2024-39910 represents a cross-site scripting vulnerability within the decidim platform, a free open-source participatory democracy system designed for cities and organizations. This vulnerability specifically affects the QuillJS WYSIWYG editor component, creating a potential attack vector where malicious actors could inject harmful scripts into the system. The flaw occurs when attackers manage to modify HTML content before it is uploaded to the server, allowing them to craft malicious requests that could compromise user sessions and potentially escalate privileges within the platform. The vulnerability stems from insufficient input validation and sanitization of HTML content processed through the QuillJS editor, which is a common pattern seen in web applications that fail to properly filter user-generated content.
The technical impact of this vulnerability aligns with CWE-79, which classifies cross-site scripting flaws as weaknesses in web applications that allow attackers to inject client-side scripts into web pages viewed by other users. This particular implementation issue demonstrates how rich text editors can become attack surfaces when they fail to properly sanitize content before rendering or storing user input. The attack vector specifically targets the HTML processing pipeline within the QuillJS component, where unfiltered content could contain malicious script tags or other harmful elements that execute in the context of authenticated users' browsers. The vulnerability's exploitation requires an attacker to have some level of access to modify content within the platform, typically through compromised accounts or by leveraging other initial access vectors.
The operational impact of CVE-2024-39910 extends beyond simple script execution, potentially allowing attackers to hijack user sessions, steal sensitive information, or escalate privileges within the participatory democracy platform. This is particularly concerning for organizations relying on decidim for citizen participation and open government initiatives, as compromised systems could undermine public trust and potentially expose sensitive participant data. The vulnerability affects the core functionality of the platform's content management system, where administrators and participants rely on the WYSIWYG editor for creating and sharing content. Attackers could leverage this flaw to inject malicious scripts that could redirect users to phishing sites, steal cookies, or perform actions on behalf of authenticated users, making this a critical security concern for any organization using the platform.
Mitigation strategies for CVE-2024-39910 should prioritize immediate patching to version 0.27.7, which contains the necessary fixes for the QuillJS HTML sanitization issues. Organizations unable to upgrade immediately should implement multiple layers of defense including strict access controls for administrative accounts, limiting who can modify content within the platform, and disabling the rich text editor functionality for participants as recommended. This aligns with the principle of least privilege and follows ATT&CK framework tactics related to privilege escalation and credential access. Security teams should also conduct thorough audits of existing user accounts with administrative privileges, removing unnecessary access where possible, and implementing monitoring for suspicious content modifications. The recommended administrative settings changes directly address the vulnerability by eliminating the attack surface through disabling the problematic editor feature, which is consistent with defensive security practices outlined in NIST SP 800-53 and similar security frameworks that emphasize input validation and privilege management as core security controls.