CVE-2023-28439Network attack vector

Script execution via unsafe iframe restoration

Published Mar 22, 2023 · Updated Feb 13, 2025

Cross-site scripting in CKEditor 4 before 4.21.0 allows remote attackers to execute JavaScript through Iframe Dialog or Media Embed content. Destroying a non-textarea editor can leave Iframe Dialog content unsandboxed or preserve unsafe Media Embed content, allowing embedded script to run. Exploitation requires an affected plugin, ineffective Content Security Policy restrictions, editor destruction, and user interaction; successful exploitation runs script in the page context.

CVSS severity4.7
Medium
EPSS probability0.73%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
Coverage for this vulnerability

See if you're affected

Explore vulnerability checks for your environment with Hinoki.

Book a demo

Summary

What happened

Cross-site scripting in CKEditor 4 before 4.21.0 allows remote attackers to execute JavaScript through Iframe Dialog or Media Embed content. Destroying a non-textarea editor can leave Iframe Dialog content unsandboxed or preserve unsafe Media Embed content, allowing embedded script to run. Exploitation requires an affected plugin, ineffective Content Security Policy restrictions, editor destruction, and user interaction; successful exploitation runs script in the page context.

The record

CVE
CVE-2023-28439
Published
Mar 22, 2023
Updated
Feb 13, 2025
Vendor
CKSource
Product
CKEditor 4
Classifications
CWE-79, T1203
Attack vector
network
Privileges
unauthenticated

Timeline

How it unfolded

  1. Mar 22, 2023CVE publishedPublication date reported by the CVE source.
  2. Feb 13, 2025Record updatedLatest update available in the CVE record.

Exploitability

Present is not the same as exploitable

Compare your product and version with the public record. A matching version still requires validation against your environment.

Is a vulnerable build present?

Compare these published version ranges with your installed build and any vendor patches.

  1. Affected versionversion=< 4.21.0

What conditions does exploitation require?

Attack vectornetwork
Required privilegesunauthenticated

What is affected?

CKSource · CKEditor 4version=< 4.21.0

Published CVSS scores

4.7GitHub, Inc.CVSS:3.1/AV:N/AC:H/PR:N/UI:R/S:C/C:L/I:L/A:N
6.1NIST NVDCVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:L/A:N

CVSS describes severity. EPSS estimates exploitation probability.

Attacks

What attackers are doing with it

Daily unique IPs observed by Shadowserver honeypots for known exploited vulnerabilities (KEVs). Missing observations do not establish an absence of attacks.

Daily unique IPsNo honeypot observations are available for this CVE in the selected window.

No observations available

Sep 10, 2026Sep 16, 2026
Latest reporting daySep 16, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectornetwork
Privilegesunauthenticated
Known exploitationUnconfirmed
Public exploitUnconfirmed

Weakness, pattern, technique

CWE-79Improper Neutralization of Input During Web Page Generation ('Cross-site Scripting')
T1203Exploitation for Client Execution

Public exploit references

No public exploit references are available in this record.

Labels summarize the accepted research assessment. They do not indicate a test against your environment.

Technologies

Your stack

See the directory against your own environment.

Your stack

Check the software in your environment

Book a demo to see how Hinoki identifies affected software and validates exploitability in your environment.

Book a demo