GHSA-rh54-vffm-5fvp: ckeditor5 (CVE-2026-116688)

Package	Ecosystem	Affected	Fixed in
ckeditor5	npm	>=45.0.0, <47.7.4 \|\| >=48.0.0, <48.5.1	47.7.4, 48.5.1
@ckeditor/ckeditor5-engine	npm	>=45.0.0, <47.7.4 \|\| >=48.0.0, <48.5.1	47.7.4, 48.5.1

Machine-written summary

Summary written by Claude Haiku from the source advisory. Not reviewed by a person.

CKEditor 5 versions from 45.0.0 up to but not including 47.7.4, and from 48.0.0 up to but not including 48.5.1, are affected through the ckeditor5 and @ckeditor/ckeditor5-engine npm packages. The source describes a cross-site scripting flaw caused by prototype pollution in the es-toolkit library, which can lead to unauthorized JavaScript execution when the editor processes incoming style attribute values; the source does not say what access an attacker needs. Upgrade ckeditor5 and @ckeditor/ckeditor5-engine to 47.7.4 or 48.5.1, which the source lists as fixed versions.

Written 31 Oct 2026.

Not analysed yet

We haven’t published our analysis of this Advisory yet. Once a person has reviewed it, this page will say what’s vulnerable, what has to be true for your app to be affected, and how to check.

Severity and exploitation

Score	Rating	CVSS	Vector	Source
8.1	High	3.1	CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:N	CNA (GitHub_M)

CISA KEV Not listed.
EPSS 0.0050, the 42nd percentile, on 7 Nov 2026: FIRST’s estimate of the chance of exploitation in the next 30 days.

Timeline

27 Oct 2026, 19:36 UTC Confirmed by the CVE List
27 Oct 2026, 20:17 UTC Confirmed by NVD
31 Oct 2026, 13:33 UTC First seen by agentprime
31 Oct 2026, 13:33 UTC Confirmed by OSV

Sources

Facts on this page come from the GitHub Advisory Database (CC-BY 4.0), OSV and the other sources listed, as published. We don’t reproduce full advisory descriptions, which can contain exploit code.