What is the CVSS score of CVE-2026-28343?

CVE-2026-28343 has a CVSS 3.1 base score of 6.4 (Medium). CVSS vector: CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:C/C:L/I:L/A:N. EPSS exploitation probability: 0.0%.

Which versions of Ckeditor5 are affected by CVE-2026-28343?

Organizations using CKEditor 5 should be aware of moderate risk from CVE-2026-28343, a cross-site scripting vulnerability rated CVSS 6.4.. A patch is available.

How to fix or mitigate CVE-2026-28343?

Within 30 days: Identify affected systems and apply vendor patches as part of regular patch cycle. Verify Content-Security-Policy and output encoding.

Ckeditor5 CVE-2026-28343

MEDIUM

Cross-site Scripting (XSS) (CWE-79)

2026-03-05 security-advisories@github.com

GHSA-jrqm-vmqc-gm93

XSS RCE Ckeditor5 Ckeditor

6.4

CVSS 3.1 · GitHub Advisory

Severity by source

GitHub Advisory PRIMARY

6.4 MEDIUM

AV:N/AC:L/PR:L/UI:N/S:C/C:L/I:L/A:N

Primary rating from GitHub Advisory · only source for this CVE.

CVSS VectorGitHub Advisory

Attack Vector

Network

Attack Complexity

Low

Privileges Required

Low

User Interaction

None

Scope

Changed

Confidentiality

Low

Integrity

Low

Availability

None

Lifecycle Timeline

Patch released

Mar 31, 2026 - 21:13 nvd

Patch available

Analysis Generated

Mar 12, 2026 - 22:06 vuln.today

CVE Published

Mar 05, 2026 - 20:16 nvd

MEDIUM 6.4

DescriptionGitHub Advisory

CKEditor 5 is a modern JavaScript rich-text editor with an MVC architecture. 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.

AnalysisAI

CKEditor 5 versions before 47.6.0 contain a stored XSS vulnerability in the General HTML Support feature that allows attackers to execute arbitrary JavaScript by injecting malicious markup into documents processed by vulnerable editor instances. This vulnerability affects users relying on unsafe General HTML Support configurations, potentially enabling session hijacking, credential theft, or malware distribution. No patch is currently available for affected deployments.

Technical ContextAI

This vulnerability (CWE-79: Cross-site Scripting (XSS)) affects CKEditor 5 is a modern JavaScript rich-text editor with an MVC architecture.. CKEditor 5 is a modern JavaScript rich-text editor with an MVC architecture. 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.

RemediationAI

Fixed in version 47.6.0.. Implement output encoding and Content Security Policy headers. Restrict network access to the affected service where possible.