CKEditor: Cross-site scripting (XSS) in the engine package

CKEditor 5 is a modern JavaScript rich-text editor with an MVC architecture. From 29.0.0 until 47.7.4 and 48.5.1, specially crafted markup can trigger cross-site scripting when General HTML Support is enabled and specifically configured to allow object content. Processing that content can execute attacker-controlled JavaScript in a browser context isolated from the origin of the application embedding the editor. This issue is fixed in versions 47.7.4 and 48.5.1.

CKEditor: Cross-site scripting (XSS) in the engine package

CKEditor 5 is a modern JavaScript rich-text editor with an MVC architecture. From 45.0.0 until 47.7.4 and 48.5.1, the engine uses a vulnerable es-toolkit version whose prototype-pollution behavior can be reached while CKEditor processes incoming style attribute values. Crafted editor content can thereby cause unauthorized JavaScript execution in the browser. This issue is fixed in versions 47.7.4 and 48.5.1.

It was possible to execute a ReDoS-type attack inside CKEditor 4 before 4.16 by persuading a victim to paste crafted text into the Styles input of specific dialogs (in the Advanced Tab for Dialogs plugin).

Advanced Content Filter (ACF) vulnerability allowing to execute JavaScript code using malformed HTML

CKEditor4 is an open source WYSIWYG HTML editor. In affected versions a vulnerability has been discovered in the Advanced Content Filter (ACF) module and may affect all plugins used by CKEditor 4. The vulnerability allowed to inject malformed HTML bypassing content sanitization, which could result in executing JavaScript code. It affects all users using the CKEditor 4 at version < 4.17.0. The problem has been recognized and patched. The fix will be available in version 4.17.0.

A cross-site scripting (XSS) vulnerability in the Color Dialog plugin for CKEditor 4.15.0 allows remote attackers to run arbitrary web script after persuading a user to copy and paste crafted HTML code into one of editor inputs.

A cross-site scripting (XSS) vulnerability in the HTML Data Processor for CKEditor 4.0 before 4.14 allows remote attackers to inject arbitrary web script through a crafted "protected" comment (with the cke_protected syntax).

It was possible to execute a ReDoS-type attack inside CKEditor 4 before 4.16 by persuading a victim to paste crafted URL-like text into the editor, and then press Enter or Space (in the Autolink plugin).

Cross-site scripting (XSS) in the real-time collaboration package

CKEditor 5 is a modern JavaScript rich-text editor with an MVC architecture. During a recent internal audit, a Cross-Site Scripting (XSS) vulnerability was discovered in the CKEditor 5 real-time collaboration package. This vulnerability affects user markers, which represent users' positions within the document. It can lead to unauthorized JavaScript code execution, which might happen with a very specific editor and token endpoint configuration. This vulnerability affects only installations with Real-time collaborative editing enabled. The problem has been recognized and patched. The fix is available in version 44.2.1 (and above). Users are advised to upgrade. There are no known workarounds for this vulnerability.

Regular expression Denial of Service in dialog plugin

CKEditor4 is an open source what-you-see-is-what-you-get HTML editor. CKEditor4 prior to version 4.18.0 contains a vulnerability in the `dialog` plugin. The vulnerability allows abuse of a dialog input validator regular expression, which can cause a significant performance drop resulting in a browser tab freeze. A patch is available in version 4.18.0. There are currently no known workarounds.

CKEditor: Cross-site scripting (XSS) in the HTML Support package

CKEditor 5 is a modern JavaScript rich-text editor with an MVC architecture. Starting in version 29.0.0 and prior to version 47.6.0, a cross-site scripting (XSS) vulnerability has been discovered in the General HTML Support feature. This vulnerability could be triggered by inserting specially crafted markup, leading to unauthorized JavaScript code execution, if the editor instance used an unsafe General HTML Support configuration. This issue has been patched in version 47.6.0.

CKEditor is susceptible to Cross-Site Scripting (XSS) through its clipboard package

CKEditor 5 is a modern JavaScript rich-text editor with an MVC architecture. ckeditor5 and ckeditor5-clipboard versions 46.0.0 through 46.0.2 and 44.2.0 through 45.2.1 contain a Cross-Site Scripting (XSS) vulnerability. Ability to exploit 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 affects installations where the editor configuration meets one of the following criteria: the HTML embed plugin is enabled, or there is a custom plugin introducing an editable element where view RawElement is enabled. This issue is fixed in versions 45.2.2 and 46.0.3 of both ckeditor5 and ckeditor5-clipboard.

CKEditor 5 Premium Features - Moderately critical - Access bypass - SA-CONTRIB-2025-118

Authentication Bypass Using an Alternate Path or Channel vulnerability in Drupal CKEditor 5 Premium Features allows Functionality Bypass.This issue affects CKEditor 5 Premium Features: from 0.0.0 before 1.2.10, from 1.3.0 before 1.3.6, from 1.4.0 before 1.4.3, from 1.5.0 before 1.5.1, from 1.6.0 before 1.6.4.

A reflected cross-site scripting (XSS) vulnerability in CKeditor v46.1.0 & Angular v18.0.0 allows attackers to execute arbitrary code in the context of a user's browser via injecting a crafted payload.

Cross-site Scripting in CKEditor4

CKEditor4 is an open source what-you-see-is-what-you-get HTML editor. A vulnerability has been discovered in the core HTML processing module and may affect all plugins used by CKEditor 4 prior to version 4.18.0. The vulnerability allows someone to inject malformed HTML bypassing content sanitization, which could result in executing JavaScript code. This problem has been patched in version 4.18.0. There are currently no known workarounds.

Cross-site scripting caused by the editor instance destroying process in ckeditor5

CKEditor 5 is a JavaScript rich text editor. A cross-site scripting vulnerability has been discovered affecting three optional CKEditor 5's packages in versions prior to 35.0.1. The vulnerability allowed to trigger a JavaScript code after fulfilling special conditions. The affected packages are `@ckeditor/ckeditor5-markdown-gfm`, `@ckeditor/ckeditor5-html-support`, and `@ckeditor/ckeditor5-html-embed`. The specific conditions are 1) Using one of the affected packages. In case of `ckeditor5-html-support` and `ckeditor5-html-embed`, additionally, it was required to use a configuration that allows unsafe markup inside the editor. 2) Destroying the editor instance and 3) Initializing the editor on an element and using an element other than `<textarea>` as a base. The root cause of the issue was a mechanism responsible for updating the source element with the markup coming from the CKEditor 5 data pipeline after destroying the editor. This vulnerability might affect a small percent of integrators that depend on dynamic editor initialization/destroy and use Markdown, General HTML Support or HTML embed features. The problem has been recognized and patched. The fix is available in version 35.0.1. There are no known workarounds for this issue.

Cross-site scripting (XSS) vulnerability in the Preview plugin before 4.4.3 in CKEditor allows remote attackers to inject arbitrary web script or HTML via unspecified vectors.

Unspecified vulnerability in the CKeditor module 6.x-2.x before 6.x-2.3 and the CKEditor module 6.x-1.x before 6.x-1.9 and 7.x-1.x before 7.x-1.7 for Drupal, when the core PHP module is enabled, allows remote authenticated users or remote attackers to execute arbitrary PHP code via the text parameter to a text filter. NOTE: some of these details are obtained from third party information.

Cross-site scripting (XSS) vulnerability in the FCKeditor module 6.x-2.x before 6.x-2.3 and the CKEditor module 6.x-1.x before 6.x-1.9 and 7.x-1.x before 7.x-1.7 for Drupal allows remote authenticated users or remote attackers to inject arbitrary web script or HTML via unspecified vectors.

CKSource CKEditor 5 35.4.0 was discovered to contain a cross-site scripting (XSS) vulnerability via the Full Featured CKEditor5 widget. NOTE: the vendor's position is that this is not a vulnerability. The CKEditor 5 documentation discusses that it is the responsibility of an integrator (who is adding CKEditor 5 functionality to a website) to choose the correct security settings for their use case. Also, safe default values are established (e.g., config.htmlEmbed.showPreviews is false).

CKEditor4 Cross-site scripting (XSS) vulnerability caused by incorrect CDATA detection

CKEditor4 is an open source what-you-see-is-what-you-get HTML editor. A cross-site scripting vulnerability has been discovered in the core HTML parsing module in versions of CKEditor4 prior to 4.24.0-lts. It may affect all editor instances that enabled full-page editing mode or enabled CDATA elements in Advanced Content Filtering configuration (defaults to `script` and `style` elements). The vulnerability allows attackers to inject malformed HTML content bypassing Advanced Content Filtering mechanism, which could result in executing JavaScript code. An attacker could abuse faulty CDATA content detection and use it to prepare an intentional attack on the editor. A fix is available in version 4.24.0-lts.