CVE-2025-58064 is a Cross-Site Scripting (XSS) vulnerability identified in CKEditor 5, a widely used modern JavaScript rich-text editor with an MVC architecture. The vulnerability affects versions 44.2.0 through 45.2.1 and 46.0.0 through 46.0.2 of both ckeditor5 and ckeditor5-clipboard. The root cause is improper neutralization of input during web page generation, specifically when malicious content is inserted into the editor under certain configurations. Exploitation requires that either the HTML embed plugin is enabled or a custom plugin introduces an editable element where the view RawElement is enabled. Under these conditions, an attacker can inject malicious JavaScript code that executes in the context of the victim’s browser when interacting with the editor content. This can lead to unauthorized script execution, potentially enabling session hijacking, defacement, or other client-side attacks. The vulnerability requires user interaction and partial attacker control over the content inserted into the editor, but does not require authentication or elevated privileges. The issue has been addressed in versions 45.2.2 and 46.0.3 of ckeditor5 and ckeditor5-clipboard. The CVSS 4.0 base score is 2.3, reflecting low severity due to the limited impact and exploitation conditions. No known exploits are reported in the wild at this time.

For European organizations, the impact of this vulnerability primarily concerns web applications and services that integrate CKEditor 5 with the vulnerable versions and configurations. If exploited, attackers could execute arbitrary JavaScript in the context of users interacting with the editor, potentially leading to theft of session tokens, user impersonation, or manipulation of displayed content. This could undermine user trust, lead to data leakage, or facilitate further attacks such as phishing or malware distribution. Organizations in sectors with high reliance on web-based content management, collaboration platforms, or customer-facing portals using CKEditor 5 are at risk. However, the low CVSS score and requirement for specific configurations and user interaction limit the overall risk. Still, the presence of this vulnerability in widely deployed open-source components means that supply chain risks and indirect exposure through third-party services are possible. European entities must consider the reputational and compliance implications, especially under GDPR, if user data is compromised through such attacks.

To mitigate this vulnerability, European organizations should: 1) Immediately upgrade all CKEditor 5 and ckeditor5-clipboard instances to versions 45.2.2 or 46.0.3 or later, where the vulnerability is fixed. 2) Review and audit editor configurations to identify if the HTML embed plugin is enabled or if any custom plugins introduce editable elements with view RawElement enabled; disable or reconfigure these features if not strictly necessary. 3) Implement Content Security Policy (CSP) headers to restrict the execution of unauthorized scripts and reduce the impact of potential XSS attacks. 4) Conduct thorough input validation and sanitization on any user-generated content before it is passed to the editor, especially if content is imported or embedded from untrusted sources. 5) Monitor web application logs and user reports for suspicious behavior indicative of XSS exploitation attempts. 6) Educate developers and administrators about secure plugin development and configuration practices to prevent similar vulnerabilities. 7) For third-party integrations using CKEditor 5, verify their versions and configurations to ensure they are not vulnerable.