CKEditor5 cross-site scripting vulnerability caused by the editor instance destroying process
Affected packages
@ckeditor/ckeditor5-markdown-gfm @ckeditor/ckeditor5-html-support @ckeditor/ckeditor5-html-embed
Impact
A cross-site scripting vulnerability has been discovered affecting three optional CKEditor 5's packages. The vulnerability allowed to trigger a JavaScript code after fulfilling special conditions:
a) 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,
b) Initializing the editor on an element and using an element other than <textarea> as a base,
c) Destroying the editor instance.
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.
Patches
The problem has been recognized and patched. The fix will be available in version 35.0.1.
For more information
Email us at security@cksource.com if you have any questions or comments about this advisory.
Affected software
Click a technology to see all vulnerabilities affecting it.
| Platform | Package | Vulnerable versions | Fixed in |
|---|---|---|---|
| npm package | @ckeditor/ckeditor5-html-embed | < 35.0.1 | 35.0.1 |
| npm package | @ckeditor/ckeditor5-html-support | < 35.0.1 | 35.0.1 |
| npm package | @ckeditor/ckeditor5-markdown-gfm | < 35.0.1 | 35.0.1 |
References
- https://github.com/ckeditor/ckeditor5/security/advisories/GHSA-42wq-rch8-6f6j
- https://nvd.nist.gov/vuln/detail/CVE-2022-31175
- https://ckeditor.com/docs/ckeditor5/latest/features/general-html-support.html
- https://ckeditor.com/docs/ckeditor5/latest/features/html-embed.html
- https://ckeditor.com/docs/ckeditor5/latest/features/markdown.html
- https://github.com/ckeditor/ckeditor5
- CVSS vector
CVSS:3.1/AV:N/AC:H/PR:N/UI:R/S:C/C:L/I:L/A:L- Weakness (CWE)
CWE-79- Platform
- npm
- Package
@ckeditor/ckeditor5-html-embed, @ckeditor/ckeditor5-html-support, @ckeditor/ckeditor5-markdown-gfm- Disclosed
- 06.08.2022
- Updated
- 11.10.2026 10:22
Sources and licenses
OSV / GitHub Advisory Database - GHSA-42wq-rch8-6f6j - CC BY 4.0
Vulnerability history: @ckeditor/ckeditor5-html-support
All published vulnerabilities of this package (npm package), newest first. Shows whether this is a one-off slip or a package that needs watching.
- Total entries
- 2
- First → latest
- 08.2022 03.2026
- Without a fix
- 0
- Exploited in attacks
- 0
Severity breakdown
- Medium 2
Disclosures per year
- 2022: 1
- 2023: 0
- 2024: 0
- 2025: 0
- 2026: 1
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