Vulnerability · Published Mar 5, 2026 · Assigned by GitHub_M

CVE-2026-28343CKEditor: Cross-site scripting (XSS) in the HTML Support package

Medium 6.4

In plain English

A medium-severity cross-site scripting in ckeditor5 from ckeditor. There are no confirmed reports of exploitation so far. The chance it is exploited in the next 30 days is estimated at 0.3% (higher than 25% of all known vulnerabilities). Fixed versions are available - upgrade the affected package.

Severity (CVSS 3.1)6.4Medium

Exploit odds (30 days)0.3%top 75.0% of all CVEs

Exploited in the wildNo reportsCISA SSVC: none

Attack toolingNoneno public tooling known

Official description

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.

Affected packages & fixed versions

Ecosystem	Package	Fixed in	Advisory
Ubuntu:25.10	ckeditor	no fix listed	UBUNTU-CVE-2026-28343
Ubuntu:22.04:LTS	ckeditor3	no fix listed	UBUNTU-CVE-2026-28343
Ubuntu:24.04:LTS	ckeditor3	no fix listed	UBUNTU-CVE-2026-28343
Ubuntu:22.04:LTS	ldap-account-manager	no fix listed	UBUNTU-CVE-2026-28343
Ubuntu:24.04:LTS	ldap-account-manager	no fix listed	UBUNTU-CVE-2026-28343
Ubuntu:25.10	ldap-account-manager	no fix listed	UBUNTU-CVE-2026-28343
Ubuntu:26.04:LTS	ldap-account-manager	no fix listed	UBUNTU-CVE-2026-28343
Ubuntu:22.04:LTS	request-tracker4	no fix listed	UBUNTU-CVE-2026-28343
Ubuntu:24.04:LTS	request-tracker4	no fix listed	UBUNTU-CVE-2026-28343
Ubuntu:25.10	request-tracker4	no fix listed	UBUNTU-CVE-2026-28343
Ubuntu:26.04:LTS	request-tracker4	no fix listed	UBUNTU-CVE-2026-28343
npm	@ckeditor/ckeditor5-html-support	47.6.0	GHSA-jrqm-vmqc-gm93
npm	ckeditor5	47.6.0	GHSA-jrqm-vmqc-gm93

Affected products (as reported)

Vendor	Product	Versions
ckeditor	ckeditor5	>= 29.0.0, < 47.6.0

Weakness: CWE-79 · Vector: CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:C/C:L/I:L/A:N

References

https://github.com/ckeditor/ckeditor5/security/advisories/GHSA-jrqm-vmqc-gm93 x_refsource_CONFIRM
https://github.com/ckeditor/ckeditor5/releases/tag/v29.0.0 x_refsource_MISC
https://github.com/ckeditor/ckeditor5/releases/tag/v47.6.0 x_refsource_MISC