CVE-2024-45613 in CKeditor5
Summary
by MITRE • 09/25/2024
CKEditor 5 is a JavaScript rich-text editor. Starting in version 40.0.0 and prior to version 43.1.1, a Cross-Site Scripting (XSS) vulnerability is present in the CKEditor 5 clipboard package. This vulnerability could be triggered by a specific user action, leading to unauthorized JavaScript code execution, if the attacker managed to insert a malicious content into the editor, which might happen with a very specific editor configuration. This vulnerability only affects installations where the Block Toolbar plugin is enabled and either the General HTML Support (with a configuration that permits unsafe markup) or the HTML Embed plugin is also enabled. A fix for the problem is available in version 43.1.1. As a workaround, one may disable the block toolbar plugin.
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Analysis
by VulDB Data Team • 03/09/2025
The vulnerability CVE-2024-45613 represents a cross-site scripting flaw within CKEditor 5's clipboard functionality that emerged in versions 40.0.0 through 43.1.0. This security weakness resides in the clipboard package component of the JavaScript rich-text editor, where malicious content can be injected through specific user interactions. The vulnerability operates under conditions that require particular editor configurations to be exploited successfully, making it context-dependent rather than universally applicable. The flaw specifically targets installations where the Block Toolbar plugin is active alongside either General HTML Support with unsafe markup permissions or the HTML Embed plugin. This combination creates a pathway for attackers to execute unauthorized JavaScript code within the victim's browser context.
The technical exploitation of this vulnerability follows a precise set of prerequisites that align with the ATT&CK framework's execution phase. The attack requires an attacker to first insert malicious content into the editor environment, which then gets processed through the clipboard handling mechanism. This process involves the Block Toolbar plugin's interaction with either the General HTML Support or HTML Embed plugin, both of which permit markup that can be interpreted as executable code. The vulnerability manifests when the editor processes clipboard data containing malicious script tags or other harmful content that bypasses normal sanitization procedures. The CWE classification for this issue would fall under CWE-79, which represents Cross-Site Scripting, specifically in the context of client-side script injection within rich text editors.
The operational impact of this vulnerability extends beyond simple script execution to potentially compromise entire user sessions and enable further attack vectors. When successfully exploited, the malicious JavaScript code can access user cookies, session tokens, and other sensitive data that the browser maintains. The vulnerability's restriction to specific plugin configurations means that not all CKEditor 5 installations are at risk, but those meeting the exact criteria become highly vulnerable to social engineering attacks where users might unknowingly paste malicious content into the editor. The attack surface expands significantly when considering that content editors often trust the editor environment, making this a particularly dangerous flaw in collaborative or content management scenarios where multiple users interact with shared editing spaces.
Organizations using CKEditor 5 should prioritize upgrading to version 43.1.1 to address the vulnerability completely. The recommended mitigation strategy includes immediate deployment of the patched version which resolves the underlying sanitization issues in the clipboard package. Alternative workarounds involve disabling the Block Toolbar plugin entirely, which removes one of the required conditions for exploitation. Security teams should also consider implementing additional content filtering measures and monitoring for unusual clipboard activity patterns that might indicate attempted exploitation. The vulnerability highlights the importance of secure input validation in rich text editors and demonstrates how seemingly benign plugin combinations can create security risks. Organizations should review their CKEditor 5 configurations to ensure that General HTML Support is not configured to permit unsafe markup unless absolutely necessary, and should conduct regular security assessments of their editor environments to identify potential attack vectors.