All vulnerabilities
CVE-2026-116688GHSA-rh54-vffm-5fvp

ckeditor5: CKEditor: Cross-site scripting (XSS) in the engine package

ckeditor ckeditor5npmLibraries & packages
Open in ThreatlineRecord JSON
CVSS
8.1High
ExploitationNo known exploitationNot in CISA KEV, which does not prove it is unexploitedCISA KEV
Exploit odds (EPSS)No scoreNo FIRST EPSS score in this snapshot yet
Fixed in47.7.4Also 48.5.1GitHub
Published27 Oct 2026Updated 27 Oct 2026CVE List

What fixes it

  • 47.7.4ckeditor5, npmGitHubnpm install ckeditor5@47.7.4
  • 47.7.4@ckeditor/ckeditor5-engine, npmGitHubnpm install @ckeditor/ckeditor5-engine@47.7.4
  • 48.5.1ckeditor5, npmGitHubnpm install ckeditor5@48.5.1
  • 48.5.1@ckeditor/ckeditor5-engine, npmGitHubnpm install @ckeditor/ckeditor5-engine@48.5.1

A fixed version on one release line is not the upgrade target for every line. Check your exact version and any vendor backports.

Description

Impact

A Cross-Site Scripting (XSS) vulnerability has been discovered in the CKEditor 5 engine. This vulnerability is caused by a prototype pollution issue in the es-toolkit library used in the CKEditor 5 codebase. This vulnerability could lead to unauthorized JavaScript code execution when the editor processes incoming style attribute values.

The underlying issue has been patched by the library maintainers, and the fix has been incorporated into CKEditor 5.

Patches

The problem has been recognized and patched. The fix will be available in version 48.5.1 (and above) and 47.7.4 (LTS).

For more information

Email us at [security@cksource.com](mailto:security@cksource.com) if you have any questions or comments about this advisory.

Text from GitHub Advisory Database

Affected versions 10

  • ckeditor5, npm>= 45.0.0, < 47.7.4GitHub
  • @ckeditor/ckeditor5-engine, npm>= 45.0.0, < 47.7.4GitHub
  • ckeditor5, npm>= 48.0.0, < 48.5.1GitHub
  • @ckeditor/ckeditor5-engine, npm>= 48.0.0, < 48.5.1GitHub
  • ckeditor5affected: >= 45.0.0, < 47.7.4CVE List
  • ckeditor5affected: >= 48.0.0, < 48.5.1CVE List
  • ckeditor5, npmfrom 45.0.0, fixed in 47.7.4OSV
  • @ckeditor/ckeditor5-engine, npmfrom 45.0.0, fixed in 47.7.4OSV
  • ckeditor5, npmfrom 48.0.0, fixed in 48.5.1OSV
  • @ckeditor/ckeditor5-engine, npmfrom 48.0.0, fixed in 48.5.1OSV

References 6