CKEditor 5 provides a WYSIWYG editing solution. This CVE affects the following npm packages: ckeditor5-engine, ckeditor5-font, ckeditor5-image, ckeditor5-list, ckeditor5-markdown-gfm, ckeditor5-media-embed, ckeditor5-paste-from-office, and ckeditor5-widget. Following an internal audit, a regular expression denial of service (ReDoS) vulnerability has been discovered in multiple CKEditor 5 packages. The vulnerability allowed to abuse particular regular expressions, which could cause a significant performance drop resulting in a browser tab freeze. It affects all users using the CKEditor 5 packages listed above at version <= 26.0.0. The problem has been recognized and patched. The fix will be available in version 27.0.0.
The product does not properly control the allocation and maintenance of a limited resource.
| Name | Vendor | Start Version | End Version |
|---|---|---|---|
| Ckeditor5-engine | Ckeditor | * | 27.0.0 (excluding) |
| Ckeditor5-font | Ckeditor | * | 27.0.0 (excluding) |
| Ckeditor5-image | Ckeditor | * | 27.0.0 (excluding) |
| Ckeditor5-list | Ckeditor | * | 27.0.0 (excluding) |
| Ckeditor5-markdown-gfm | Ckeditor | * | 27.0.0 (excluding) |
| Ckeditor5-media-embed | Ckeditor | * | 27.0.0 (excluding) |
| Ckeditor5-paste-from-office | Ckeditor | * | 27.0.0 (excluding) |
| Ckeditor5-widget | Ckeditor | * | 27.0.0 (excluding) |
| Ckeditor | Ubuntu | groovy | * |
| Ckeditor | Ubuntu | hirsute | * |
| Ckeditor | Ubuntu | trusty | * |
| Ckeditor | Ubuntu | xenial | * |
| Ckeditor3 | Ubuntu | bionic | * |
| Ckeditor3 | Ubuntu | focal | * |
| Ckeditor3 | Ubuntu | groovy | * |
| Ckeditor3 | Ubuntu | hirsute | * |
| Ckeditor3 | Ubuntu | impish | * |
| Ckeditor3 | Ubuntu | kinetic | * |
| Ckeditor3 | Ubuntu | lunar | * |
| Ckeditor3 | Ubuntu | mantic | * |
| Ckeditor3 | Ubuntu | oracular | * |
| Ckeditor3 | Ubuntu | trusty | * |
Mitigation of resource exhaustion attacks requires that the target system either:
The first of these solutions is an issue in itself though, since it may allow attackers to prevent the use of the system by a particular valid user. If the attacker impersonates the valid user, they may be able to prevent the user from accessing the server in question.
The second solution is simply difficult to effectively institute – and even when properly done, it does not provide a full solution. It simply makes the attack require more resources on the part of the attacker.