CVE-2020-27193

Vulnerability

Overview

CVE-2020-27193 is a cross-site scripting (XSS) vulnerability found in the Color Dialog plugin of CKEditor 4.15.0. The root cause lies in insufficient sanitization of user-supplied HTML content within the color picker dialog inputs. When a user copies and pastes specially crafted HTML code into one of these inputs, the script is not properly escaped or filtered before being rendered back to the user [1][3].

Exploitation

Prerequisites

To exploit this vulnerability, an attacker must first craft malicious HTML payload designed to execute arbitrary web script. The attacker then needs to persuade a victim to copy that crafted HTML and paste it into a CKEditor 4.15.0 field that utilizes the Color Dialog plugin. The attack requires user interaction (the paste action) and does not rely on any prior authentication level, making it a client-side manipulation vector within the editor's interface [3].

Impact

A successful exploit allows the attacker to execute arbitrary web script in the context of the victim's session within the application using CKEditor. This can lead to data theft, session hijacking, or further injection attacks, depending on the application's trust boundaries and the privileges of the victim's session. The vulnerability is particularly concerning because rich-text editors are often used in content management systems, forums, or email composition interfaces, where a single compromised input could lead to broader cross-site scripting consequences [1][3].

Mitigation and

Status

The vulnerability was addressed in CKEditor version 4.15.1, released in November 2020 [1][3]. Users are strongly advised to upgrade to this patched version or later. However, CKEditor 4 reached its End of Life (EOL) on June 30, 2023, meaning no further security patches are provided for the open-source version beyond 4.22.1 [2]. A commercial Extended Support Model (CKEditor 4 LTS) is available for continued security updates until December 2028 [2][4]. For long-term security, migration to CKEditor 5 is recommended, though it requires careful planning due to breaking changes [1][2].